diff --git a/Cargo.lock b/Cargo.lock
index 66ce5f990..a9511676c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -131,6 +131,103 @@ dependencies = [
  "libloading",
 ]
 
+[[package]]
+name = "ashpd"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6dcc8ed0b5211687437636d8c95f6a608f4281d142101b3b5d314b38bfadd40f"
+dependencies = [
+ "enumflags2",
+ "futures",
+ "rand",
+ "serde",
+ "serde_repr",
+ "zbus",
+]
+
+[[package]]
+name = "async-broadcast"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d26004fe83b2d1cd3a97609b21e39f9a31535822210fe83205d2ce48866ea61"
+dependencies = [
+ "event-listener",
+ "futures-core",
+ "parking_lot",
+]
+
+[[package]]
+name = "async-channel"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e14485364214912d3b19cc3435dde4df66065127f05fa0d75c712f36f12c2f28"
+dependencies = [
+ "concurrent-queue",
+ "event-listener",
+ "futures-core",
+]
+
+[[package]]
+name = "async-executor"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "871f9bb5e0a22eeb7e8cf16641feb87c9dc67032ccf8ff49e772eb9941d3a965"
+dependencies = [
+ "async-task",
+ "concurrent-queue",
+ "fastrand",
+ "futures-lite",
+ "once_cell",
+ "slab",
+]
+
+[[package]]
+name = "async-io"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8121296a9f05be7f34aa4196b1747243b3b62e048bb7906f644f3fbfc490cf7"
+dependencies = [
+ "async-lock",
+ "autocfg",
+ "concurrent-queue",
+ "futures-lite",
+ "libc",
+ "log",
+ "parking",
+ "polling",
+ "slab",
+ "socket2",
+ "waker-fn",
+ "winapi",
+]
+
+[[package]]
+name = "async-lock"
+version = "2.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8101efe8695a6c17e02911402145357e718ac92d3ff88ae8419e84b1707b685"
+dependencies = [
+ "event-listener",
+ "futures-lite",
+]
+
+[[package]]
+name = "async-recursion"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7d78656ba01f1b93024b7c3a0467f1608e4be67d725749fdcd7d2c7678fd7a2"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "async-task"
+version = "4.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a40729d2133846d9ed0ea60a8b9541bccddab49cd30f0715a1da672fe9a2524"
+
 [[package]]
 name = "async-trait"
 version = "0.1.58"
@@ -293,6 +390,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c4872d67bab6358e59559027aa3b9157c53d9358c51423c17554809a8858e0f8"
 
+[[package]]
+name = "cache-padded"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1db59621ec70f09c5e9b597b220c7a2b43611f4710dc03ceb8748637775692c"
+
 [[package]]
 name = "calloop"
 version = "0.10.1"
@@ -300,7 +403,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a22a6a8f622f797120d452c630b0ab12e1331a1a753e2039ce7868d4ac77b4ee"
 dependencies = [
  "log",
- "nix",
+ "nix 0.24.2",
  "slotmap",
  "thiserror",
  "vec_map",
@@ -484,6 +587,15 @@ dependencies = [
  "unicode-width",
 ]
 
+[[package]]
+name = "concurrent-queue"
+version = "1.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af4780a44ab5696ea9e28294517f1fffb421a83a25af521333c838635509db9c"
+dependencies = [
+ "cache-padded",
+]
+
 [[package]]
 name = "copyless"
 version = "0.1.5"
@@ -750,12 +862,43 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "derivative"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fcc3dd5e9e9c0b295d6e1e4d811fb6f157d5ffd784b8d202fc62eac8035a770b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "diff"
 version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56254986775e3233ffa9c4d7d3faaf6d36a2c09d30b20687e9f88bc8bafc16c8"
 
+[[package]]
+name = "dirs"
+version = "4.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3aa72a6f96ea37bbc5aa912f6788242832f75369bdfdadcb0e38423f100059"
+dependencies = [
+ "dirs-sys",
+]
+
+[[package]]
+name = "dirs-sys"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b1d1d91c932ef41c0f2663aa8b0ca0342d444d842c06914aa0a7e352d0bada6"
+dependencies = [
+ "libc",
+ "redox_users",
+ "winapi",
+]
+
 [[package]]
 name = "dispatch"
 version = "0.2.0"
@@ -858,6 +1001,27 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "enumflags2"
+version = "0.7.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e75d4cd21b95383444831539909fbb14b9dc3fdceb2a6f5d36577329a1f55ccb"
+dependencies = [
+ "enumflags2_derive",
+ "serde",
+]
+
+[[package]]
+name = "enumflags2_derive"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f58dc3c5e468259f19f2d46304a6b28f1c3d034442e14b322d2b850e36f6d5ae"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "env_logger"
 version = "0.9.1"
@@ -886,6 +1050,12 @@ dependencies = [
  "parking_lot",
 ]
 
+[[package]]
+name = "event-listener"
+version = "2.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0206175f82b8d6bf6652ff7d71a1e27fd2e4efde587fd368662814d6ec1d9ce0"
+
 [[package]]
 name = "expat-sys"
 version = "2.1.6"
@@ -1067,12 +1237,14 @@ name = "fj-viewer"
 version = "0.21.0"
 dependencies = [
  "bytemuck",
+ "crossbeam-channel",
  "egui",
  "egui-wgpu",
  "fj-interop",
  "fj-math",
  "getrandom",
  "raw-window-handle 0.4.3",
+ "rfd",
  "thiserror",
  "tracing",
  "wgpu",
@@ -1083,6 +1255,7 @@ dependencies = [
 name = "fj-window"
 version = "0.21.0"
 dependencies = [
+ "crossbeam-channel",
  "egui-winit",
  "fj-host",
  "fj-interop",
@@ -1241,6 +1414,21 @@ version = "0.3.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "00f5fb52a06bdcadeb54e8d3671f8888a39697dcb0b81b23b55174030427f4eb"
 
+[[package]]
+name = "futures-lite"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7694489acd39452c77daa48516b894c153f192c3578d5a839b62c58099fcbf48"
+dependencies = [
+ "fastrand",
+ "futures-core",
+ "futures-io",
+ "memchr",
+ "parking",
+ "pin-project-lite",
+ "waker-fn",
+]
+
 [[package]]
 name = "futures-macro"
 version = "0.3.25"
@@ -1443,6 +1631,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
 [[package]]
 name = "hexf-parse"
 version = "0.2.1"
@@ -2010,6 +2204,19 @@ dependencies = [
  "jni-sys",
 ]
 
+[[package]]
+name = "nix"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f866317acbd3a240710c63f065ffb1e4fd466259045ccb504130b7f668f35c6"
+dependencies = [
+ "bitflags",
+ "cc",
+ "cfg-if",
+ "libc",
+ "memoffset",
+]
+
 [[package]]
 name = "nix"
 version = "0.24.2"
@@ -2178,6 +2385,17 @@ dependencies = [
  "objc_exception",
 ]
 
+[[package]]
+name = "objc-foundation"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1add1b659e36c9607c7aab864a76c7a4c2760cd0cd2e120f3fb8b952c7e22bf9"
+dependencies = [
+ "block",
+ "objc",
+ "objc_id",
+]
+
 [[package]]
 name = "objc_exception"
 version = "0.1.2"
@@ -2187,6 +2405,15 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "objc_id"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c92d4ddb4bd7b50d730c215ff871754d0da6b2178849f8a2a2ab69712d0c073b"
+dependencies = [
+ "objc",
+]
+
 [[package]]
 name = "object"
 version = "0.29.0"
@@ -2286,6 +2513,16 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "ordered-stream"
+version = "0.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44630c059eacfd6e08bdaa51b1db2ce33119caa4ddc1235e923109aa5f25ccb1"
+dependencies = [
+ "futures-core",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "os_pipe"
 version = "0.9.2"
@@ -2326,6 +2563,12 @@ dependencies = [
  "ttf-parser",
 ]
 
+[[package]]
+name = "parking"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "427c3892f9e783d91cc128285287e70a59e206ca452770ece88a76f7a3eddd72"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -2465,6 +2708,26 @@ dependencies = [
  "miniz_oxide",
 ]
 
+[[package]]
+name = "polling"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab4609a838d88b73d8238967b60dd115cc08d38e2bbaf51ee1e4b695f89122e2"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "libc",
+ "log",
+ "wepoll-ffi",
+ "winapi",
+]
+
+[[package]]
+name = "pollster"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5da3b0203fd7ee5720aa0b5e790b591aa5d3f41c3ed2c34a3a393382198af2f7"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.16"
@@ -2648,6 +2911,17 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "redox_users"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b033d837a7cf162d7993aded9304e30a83213c648b6e389db233191f891e5c2b"
+dependencies = [
+ "getrandom",
+ "redox_syscall",
+ "thiserror",
+]
+
 [[package]]
 name = "regex"
 version = "1.6.0"
@@ -2745,6 +3019,29 @@ dependencies = [
  "winreg",
 ]
 
+[[package]]
+name = "rfd"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0149778bd99b6959285b0933288206090c50e2327f47a9c463bfdbf45c8823ea"
+dependencies = [
+ "ashpd",
+ "block",
+ "dispatch",
+ "js-sys",
+ "log",
+ "objc",
+ "objc-foundation",
+ "objc_id",
+ "pollster",
+ "raw-window-handle 0.5.0",
+ "urlencoding",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "windows",
+]
+
 [[package]]
 name = "ring"
 version = "0.16.20"
@@ -2950,6 +3247,17 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_repr"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fe39d9fbb0ebf5eb2c7cb7e2a47e4f462fad1379f1166b8ae49ad9eae89a7ca"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "serde_urlencoded"
 version = "0.7.1"
@@ -2983,6 +3291,21 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "sha1"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1da05c97445caa12d05e848c4a4fcbbea29e748ac28f7e80e9b010392063770"
+dependencies = [
+ "sha1_smol",
+]
+
+[[package]]
+name = "sha1_smol"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae1a47186c03a32177042e55dbc5fd5aee900b8e0069a8d70fba96a9375cd012"
+
 [[package]]
 name = "sharded-slab"
 version = "0.1.4"
@@ -3062,7 +3385,7 @@ dependencies = [
  "lazy_static",
  "log",
  "memmap2",
- "nix",
+ "nix 0.24.2",
  "pkg-config",
  "wayland-client",
  "wayland-cursor",
@@ -3501,6 +3824,16 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dcf81ac59edc17cc8697ff311e8f5ef2d99fcbd9817b34cec66f90b6c3dfd987"
 
+[[package]]
+name = "uds_windows"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce65604324d3cce9b966701489fbd0cf318cb1f7bd9dd07ac9a4ee6fb791930d"
+dependencies = [
+ "tempfile",
+ "winapi",
+]
+
 [[package]]
 name = "uncased"
 version = "0.9.7"
@@ -3570,6 +3903,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "urlencoding"
+version = "2.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8db7427f936968176eaa7cdf81b7f98b980b18495ec28f1b5791ac3bfe3eea9"
+
 [[package]]
 name = "valuable"
 version = "0.1.0"
@@ -3594,6 +3933,12 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "waker-fn"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d5b2c62b4012a3e1eca5a7e077d13b3bf498c4073e33ccd58626607748ceeca"
+
 [[package]]
 name = "walkdir"
 version = "2.3.2"
@@ -3702,7 +4047,7 @@ dependencies = [
  "bitflags",
  "downcast-rs",
  "libc",
- "nix",
+ "nix 0.24.2",
  "scoped-tls",
  "wayland-commons",
  "wayland-scanner",
@@ -3715,7 +4060,7 @@ version = "0.29.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8691f134d584a33a6606d9d717b95c4fa20065605f798a3f350d78dced02a902"
 dependencies = [
- "nix",
+ "nix 0.24.2",
  "once_cell",
  "smallvec",
  "wayland-sys",
@@ -3727,7 +4072,7 @@ version = "0.29.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6865c6b66f13d6257bef1cd40cbfe8ef2f150fb8ebbdb1e8e873455931377661"
 dependencies = [
- "nix",
+ "nix 0.24.2",
  "wayland-client",
  "xcursor",
 ]
@@ -3776,6 +4121,15 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "wepoll-ffi"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d743fdedc5c64377b5fc2bc036b01c7fd642205a0d96356034ae3404d49eb7fb"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "wgpu"
 version = "0.13.1"
@@ -3923,6 +4277,19 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
+[[package]]
+name = "windows"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57b543186b344cc61c85b5aab0d2e3adf4e0f99bc076eff9aa5927bcc0b8a647"
+dependencies = [
+ "windows_aarch64_msvc 0.37.0",
+ "windows_i686_gnu 0.37.0",
+ "windows_i686_msvc 0.37.0",
+ "windows_x86_64_gnu 0.37.0",
+ "windows_x86_64_msvc 0.37.0",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.36.1"
@@ -3963,6 +4330,12 @@ version = "0.36.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9bb8c3fd39ade2d67e9874ac4f3db21f0d710bee00fe7cab16949ec184eeaa47"
 
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2623277cb2d1c216ba3b578c0f3cf9cdebeddb6e66b1b218bb33596ea7769c3a"
+
 [[package]]
 name = "windows_aarch64_msvc"
 version = "0.42.0"
@@ -3975,6 +4348,12 @@ version = "0.36.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "180e6ccf01daf4c426b846dfc66db1fc518f074baa793aa7d9b9aaeffad6a3b6"
 
+[[package]]
+name = "windows_i686_gnu"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3925fd0b0b804730d44d4b6278c50f9699703ec49bcd628020f46f4ba07d9e1"
+
 [[package]]
 name = "windows_i686_gnu"
 version = "0.42.0"
@@ -3987,6 +4366,12 @@ version = "0.36.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2e7917148b2812d1eeafaeb22a97e4813dfa60a3f8f78ebe204bcc88f12f024"
 
+[[package]]
+name = "windows_i686_msvc"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce907ac74fe331b524c1298683efbf598bb031bc84d5e274db2083696d07c57c"
+
 [[package]]
 name = "windows_i686_msvc"
 version = "0.42.0"
@@ -3999,6 +4384,12 @@ version = "0.36.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4dcd171b8776c41b97521e5da127a2d86ad280114807d0b2ab1e462bc764d9e1"
 
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2babfba0828f2e6b32457d5341427dcbb577ceef556273229959ac23a10af33d"
+
 [[package]]
 name = "windows_x86_64_gnu"
 version = "0.42.0"
@@ -4017,6 +4408,12 @@ version = "0.36.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c811ca4a8c853ef420abd8592ba53ddbbac90410fab6903b3e79972a631f7680"
 
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.37.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4dd6dc7df2d84cf7b33822ed5b86318fb1781948e9663bacd047fc9dd52259d"
+
 [[package]]
 name = "windows_x86_64_msvc"
 version = "0.42.0"
@@ -4112,6 +4509,70 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09041cd90cf85f7f8b2df60c646f853b7f535ce68f85244eb6731cf89fa498ec"
 
+[[package]]
+name = "zbus"
+version = "2.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d8f1a037b2c4a67d9654dc7bdfa8ff2e80555bbefdd3c1833c1d1b27c963a6b"
+dependencies = [
+ "async-broadcast",
+ "async-channel",
+ "async-executor",
+ "async-io",
+ "async-lock",
+ "async-recursion",
+ "async-task",
+ "async-trait",
+ "byteorder 1.4.3",
+ "derivative",
+ "dirs",
+ "enumflags2",
+ "event-listener",
+ "futures-core",
+ "futures-sink",
+ "futures-util",
+ "hex",
+ "lazy_static",
+ "nix 0.23.1",
+ "once_cell",
+ "ordered-stream",
+ "rand",
+ "serde",
+ "serde_repr",
+ "sha1",
+ "static_assertions",
+ "tracing",
+ "uds_windows",
+ "winapi",
+ "zbus_macros",
+ "zbus_names",
+ "zvariant",
+]
+
+[[package]]
+name = "zbus_macros"
+version = "2.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f8fb5186d1c87ae88cf234974c240671238b4a679158ad3b94ec465237349a6"
+dependencies = [
+ "proc-macro-crate",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "syn",
+]
+
+[[package]]
+name = "zbus_names"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41a408fd8a352695690f53906dc7fd036be924ec51ea5e05666ff42685ed0af5"
+dependencies = [
+ "serde",
+ "static_assertions",
+ "zvariant",
+]
+
 [[package]]
 name = "zeroize"
 version = "1.5.7"
@@ -4129,3 +4590,29 @@ dependencies = [
  "crossbeam-utils",
  "flate2",
 ]
+
+[[package]]
+name = "zvariant"
+version = "3.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b794fb7f59af4105697b0449ba31731ee5dbb3e773a17dbdf3d36206ea1b1644"
+dependencies = [
+ "byteorder 1.4.3",
+ "enumflags2",
+ "libc",
+ "serde",
+ "static_assertions",
+ "zvariant_derive",
+]
+
+[[package]]
+name = "zvariant_derive"
+version = "3.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd58d4b6c8e26d3dd2149c8c40c6613ef6451b9885ff1296d1ac86c388351a54"
+dependencies = [
+ "proc-macro-crate",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
diff --git a/crates/fj-app/src/main.rs b/crates/fj-app/src/main.rs
index b89c9cd70..e8ab235a5 100644
--- a/crates/fj-app/src/main.rs
+++ b/crates/fj-app/src/main.rs
@@ -16,6 +16,7 @@ mod args;
 mod config;
 mod path;
 
+use anyhow::{anyhow, Context};
 use fj_export::export;
 use fj_host::Parameters;
 use fj_operations::shape_processor::ShapeProcessor;
@@ -42,18 +43,18 @@ fn main() -> anyhow::Result<()> {
 
     let args = Args::parse();
     let config = Config::load()?;
-    let model_path = ModelPath::from_args_and_config(&args, &config)?;
+    let model_path = ModelPath::from_args_and_config(&args, &config);
     let parameters = args.parameters.unwrap_or_else(Parameters::empty);
     let shape_processor = ShapeProcessor {
         tolerance: args.tolerance,
     };
 
-    let model = model_path.load_model(parameters)?;
+    let model = model_path.map(|m| m.load_model(parameters)).transpose()?;
 
     if let Some(export_path) = args.export {
         // export only mode. just load model, process, export and exit
 
-        let evaluation = model.evaluate()?;
+        let evaluation = model.with_context(no_model_error)?.evaluate()?;
         let shape = shape_processor.process(&evaluation.shape)?;
 
         export(&shape.mesh, &export_path)?;
@@ -66,3 +67,11 @@ fn main() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+fn no_model_error() -> anyhow::Error {
+    anyhow!(
+        "You must specify a model to start Fornjot in export only mode.\n\
+        - Pass a model as a command-line argument. See `fj-app --help`.\n\
+        - Specify a default model in the configuration file."
+    )
+}
diff --git a/crates/fj-app/src/path.rs b/crates/fj-app/src/path.rs
index 3fd33d361..5d0a7c02e 100644
--- a/crates/fj-app/src/path.rs
+++ b/crates/fj-app/src/path.rs
@@ -3,7 +3,7 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use anyhow::{anyhow, Context};
+use anyhow::Context;
 use fj_host::{Model, Parameters};
 
 use crate::{args::Args, config::Config};
@@ -14,10 +14,7 @@ pub struct ModelPath {
 }
 
 impl ModelPath {
-    pub fn from_args_and_config(
-        args: &Args,
-        config: &Config,
-    ) -> anyhow::Result<Self> {
+    pub fn from_args_and_config(args: &Args, config: &Config) -> Option<Self> {
         let default_path = config.default_path.clone();
 
         let model_path_from_args = args
@@ -28,11 +25,9 @@ impl ModelPath {
             .default_model
             .as_ref()
             .map(|model| ModelPathSource::Config(model.clone()));
-        let model_path = model_path_from_args
-            .or(model_path_from_config)
-            .ok_or_else(no_model_error)?;
+        let model_path = model_path_from_args.or(model_path_from_config)?;
 
-        Ok(Self {
+        Some(Self {
             default_path,
             model_path,
         })
@@ -142,11 +137,3 @@ fn load_error_context_inner(
 
     Ok(context)
 }
-
-fn no_model_error() -> anyhow::Error {
-    anyhow!(
-        "You must specify a model to start Fornjot.\n\
-        - Pass a model as a command-line argument. See `fj-app --help`.\n\
-        - Specify a default model in the configuration file."
-    )
-}
diff --git a/crates/fj-host/src/host.rs b/crates/fj-host/src/host.rs
index 191423c5c..948946468 100644
--- a/crates/fj-host/src/host.rs
+++ b/crates/fj-host/src/host.rs
@@ -16,7 +16,10 @@ impl Host {
     pub fn from_model(model: Model) -> Result<Self, Error> {
         let watch_path = model.watch_path();
         let evaluator = Evaluator::from_model(model);
-        let _watcher = Watcher::watch_model(&watch_path, &evaluator)?;
+        let _watcher = match Watcher::watch_model(&watch_path, &evaluator) {
+            Ok(_watcher) => _watcher,
+            Err(e) => return Err(e),
+        };
 
         Ok(Self {
             evaluator,
diff --git a/crates/fj-viewer/Cargo.toml b/crates/fj-viewer/Cargo.toml
index 9c18ed9e9..58b8b6e2f 100644
--- a/crates/fj-viewer/Cargo.toml
+++ b/crates/fj-viewer/Cargo.toml
@@ -12,6 +12,7 @@ categories.workspace = true
 
 [dependencies]
 bytemuck = "1.12.1"
+crossbeam-channel = "0.5.6"
 egui = "0.19.0"
 egui-wgpu = "0.19.0"
 fj-interop.workspace = true
@@ -21,6 +22,11 @@ thiserror = "1.0.35"
 tracing = "0.1.37"
 wgpu_glyph = "0.17.0"
 
+[dependencies.rfd]
+version = "0.10.0"
+default_features = false
+features = ["xdg-portal"]
+
 [dependencies.wgpu]
 version = "0.13.1"
 features = ["webgl"]
diff --git a/crates/fj-viewer/src/graphics/renderer.rs b/crates/fj-viewer/src/graphics/renderer.rs
index cea4a85ce..4912ab30d 100644
--- a/crates/fj-viewer/src/graphics/renderer.rs
+++ b/crates/fj-viewer/src/graphics/renderer.rs
@@ -1,5 +1,6 @@
-use std::{io, mem::size_of};
+use std::{io, mem::size_of, path::PathBuf};
 
+use crossbeam_channel::{Receiver, Sender};
 use thiserror::Error;
 use tracing::debug;
 use wgpu::util::DeviceExt as _;
@@ -171,8 +172,12 @@ impl Renderer {
         })
     }
 
-    pub(crate) fn init_gui(&self) -> Gui {
-        Gui::new(&self.device, self.surface_config.format)
+    pub(crate) fn init_gui(
+        &self,
+        event_rx: Receiver<()>,
+        event_tx: Sender<PathBuf>,
+    ) -> Gui {
+        Gui::new(&self.device, self.surface_config.format, event_rx, event_tx)
     }
 
     /// Updates the geometry of the model being rendered.
diff --git a/crates/fj-viewer/src/gui.rs b/crates/fj-viewer/src/gui.rs
index 056e5b92d..6c1fad6d3 100644
--- a/crates/fj-viewer/src/gui.rs
+++ b/crates/fj-viewer/src/gui.rs
@@ -14,22 +14,47 @@
 //!
 //! <https://github.com/gfx-rs/wgpu/issues/1492>
 
+use std::path::PathBuf;
+
+#[cfg(not(target_arch = "wasm32"))]
+use std::env::current_dir;
+
+use crossbeam_channel::{Receiver, Sender};
+
+#[cfg(not(target_arch = "wasm32"))]
+use rfd::FileDialog;
+
 use fj_interop::status_report::StatusReport;
 use fj_math::{Aabb, Scalar};
 
 use crate::graphics::DrawConfig;
 
+struct GuiState {
+    has_model: bool,
+}
+
+impl Default for GuiState {
+    fn default() -> Self {
+        Self { has_model: true }
+    }
+}
+
 /// The GUI
 pub struct Gui {
     context: egui::Context,
     render_pass: egui_wgpu::renderer::RenderPass,
     options: Options,
+    event_rx: Receiver<()>,
+    event_tx: Sender<PathBuf>,
+    state: GuiState,
 }
 
 impl Gui {
     pub(crate) fn new(
         device: &wgpu::Device,
         texture_format: wgpu::TextureFormat,
+        event_rx: Receiver<()>,
+        event_tx: Sender<PathBuf>,
     ) -> Self {
         // The implementation of the integration with `egui` is likely to need
         // to change "significantly" depending on what architecture approach is
@@ -69,6 +94,9 @@ impl Gui {
             context,
             render_pass,
             options: Default::default(),
+            event_rx,
+            event_tx,
+            state: Default::default(),
         }
     }
 
@@ -86,6 +114,23 @@ impl Gui {
         status: &StatusReport,
         line_drawing_available: bool,
     ) {
+        loop {
+            let gui_event = self
+                .event_rx
+                .try_recv()
+                .map_err(|err| {
+                    if err.is_disconnected() {
+                        panic!("Expected channel to never disconnect");
+                    }
+                })
+                .ok();
+
+            match gui_event {
+                Some(_) => self.state.has_model = false,
+                None => break,
+            };
+        }
+
         self.context.set_pixels_per_point(pixels_per_point);
         self.context.begin_frame(egui_input);
 
@@ -243,6 +288,32 @@ impl Gui {
                 ))
             })
         });
+
+        if !self.state.has_model {
+            egui::Area::new("ask-model")
+                .anchor(egui::Align2::CENTER_CENTER, [0_f32, -5_f32])
+                .show(&self.context, |ui| {
+                    ui.vertical_centered(|ui| {
+                        ui.label(egui::RichText::new(
+                            "No model selected please choose a model to view.",
+                        ).color(egui::Color32::BLACK)
+                        .background_color(egui::Color32::WHITE));
+                        if ui
+                            .button(egui::RichText::new("Pick a model"))
+                            .clicked()
+                        {
+                            let model_dir = show_file_dialog();
+                            if let Some(model_dir) = model_dir {
+                                self.event_tx
+                                    .send(model_dir)
+                                    .expect("Channel is disconnected");
+
+                                self.state.has_model = true;
+                            }
+                        }
+                    })
+                });
+        }
     }
 
     pub(crate) fn draw(
@@ -281,6 +352,16 @@ impl Gui {
     }
 }
 
+fn show_file_dialog() -> Option<PathBuf> {
+    #[cfg(not(target_arch = "wasm32"))]
+    return FileDialog::new()
+        .set_directory(current_dir().unwrap_or_else(|_| PathBuf::from("/")))
+        .pick_folder();
+
+    #[cfg(target_arch = "wasm32")]
+    todo!("Picking folders does not work on wasm32")
+}
+
 impl std::fmt::Debug for Gui {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.write_str("Gui {}")
diff --git a/crates/fj-viewer/src/viewer.rs b/crates/fj-viewer/src/viewer.rs
index 7f53e9d5c..c0520084f 100644
--- a/crates/fj-viewer/src/viewer.rs
+++ b/crates/fj-viewer/src/viewer.rs
@@ -1,9 +1,13 @@
+use std::path::PathBuf;
+
 use fj_interop::{
     processed_shape::ProcessedShape, status_report::StatusReport,
 };
 use fj_math::Aabb;
 use tracing::warn;
 
+use crossbeam_channel::{Receiver, Sender};
+
 use crate::{
     camera::FocusPoint, gui::Gui, Camera, DrawConfig, InputEvent, InputHandler,
     NormalizedScreenPosition, Renderer, RendererInitError, Screen, ScreenSize,
@@ -38,9 +42,13 @@ pub struct Viewer {
 
 impl Viewer {
     /// Construct a new instance of `Viewer`
-    pub async fn new(screen: &impl Screen) -> Result<Self, RendererInitError> {
+    pub async fn new(
+        screen: &impl Screen,
+        event_rx: Receiver<()>,
+        event_tx: Sender<PathBuf>,
+    ) -> Result<Self, RendererInitError> {
         let renderer = Renderer::new(screen).await?;
-        let gui = renderer.init_gui();
+        let gui = renderer.init_gui(event_rx, event_tx);
 
         Ok(Self {
             camera: Camera::default(),
diff --git a/crates/fj-window/Cargo.toml b/crates/fj-window/Cargo.toml
index 551c4e8ea..684269adb 100644
--- a/crates/fj-window/Cargo.toml
+++ b/crates/fj-window/Cargo.toml
@@ -15,6 +15,7 @@ fj-host.workspace = true
 fj-operations.workspace = true
 fj-viewer.workspace = true
 fj-interop.workspace = true
+crossbeam-channel = "0.5.6"
 futures = "0.3.25"
 thiserror = "1.0.35"
 tracing = "0.1.37"
diff --git a/crates/fj-window/src/run.rs b/crates/fj-window/src/run.rs
index a47c38ec5..4bc91f38b 100644
--- a/crates/fj-window/src/run.rs
+++ b/crates/fj-window/src/run.rs
@@ -3,9 +3,9 @@
 //! Provides the functionality to create a window and perform basic viewing
 //! with programmed models.
 
-use std::error;
+use std::{error, path::PathBuf};
 
-use fj_host::{Host, Model, ModelEvent};
+use fj_host::{Host, Model, ModelEvent, Parameters};
 use fj_interop::status_report::StatusReport;
 use fj_operations::shape_processor::ShapeProcessor;
 use fj_viewer::{
@@ -27,23 +27,31 @@ use crate::window::{self, Window};
 
 /// Initializes a model viewer for a given model and enters its process loop.
 pub fn run(
-    model: Model,
+    model: Option<Model>,
     shape_processor: ShapeProcessor,
     invert_zoom: bool,
 ) -> Result<(), Error> {
+    let (send_gui, gui_event_rx) = crossbeam_channel::bounded::<()>(1);
+    let (gui_event_tx, recv_gui) = crossbeam_channel::bounded::<PathBuf>(1);
+
     let mut status = StatusReport::new();
-    let host = Host::from_model(model)?;
 
     let event_loop = EventLoop::new();
     let window = Window::new(&event_loop)?;
-    let mut viewer = block_on(Viewer::new(&window))?;
-
-    let events = host.events();
+    let mut viewer =
+        block_on(Viewer::new(&window, gui_event_rx, gui_event_tx))?;
 
     let mut held_mouse_button = None;
 
     let mut egui_winit_state = egui_winit::State::new(&event_loop);
 
+    let mut host = None;
+    if let Some(model) = model {
+        host = Some(Host::from_model(model)?);
+    } else {
+        send_gui.send(()).expect("Channel is disconnected");
+    }
+
     // Only handle resize events once every frame. This filters out spurious
     // resize events that can lead to wgpu warnings. See this issue for some
     // context:
@@ -53,52 +61,90 @@ pub fn run(
     event_loop.run(move |event, _, control_flow| {
         trace!("Handling event: {:?}", event);
 
-        loop {
-            let event = events
-                .try_recv()
-                .map_err(|err| {
-                    if err.is_disconnected() {
-                        panic!("Expected channel to never disconnect");
-                    }
-                })
-                .ok();
+        let gui_event = recv_gui
+            .try_recv()
+            .map_err(|err| {
+                if err.is_disconnected() {
+                    panic!("Expected channel to never disconnect");
+                }
+            })
+            .ok();
+
+        if let Some(model_path) = gui_event {
+            let model = Model::new(model_path, Parameters::empty()).unwrap();
+            match Host::from_model(model) {
+                Ok(new_host) => {
+                    host = Some(new_host);
+                }
+                Err(_) => {
+                    status.update_status("Error creating host.");
+                    send_gui.send(()).expect("Channel is disconnected");
+                }
+            }
+        }
 
-            let event = match event {
-                Some(status_update) => status_update,
-                None => break,
-            };
+        if let Some(host) = &host {
+            loop {
+                let events = host.events();
+                let event = events
+                    .try_recv()
+                    .map_err(|err| {
+                        if err.is_disconnected() {
+                            panic!("Expected channel to never disconnect");
+                        }
+                    })
+                    .ok();
+
+                let event = match event {
+                    Some(status_update) => status_update,
+                    None => break,
+                };
+
+                match event {
+                    ModelEvent::Evaluation(evaluation) => {
+                        status.update_status(&format!(
+                            "Model compiled successfully in {}!",
+                            evaluation.compile_time
+                        ));
+
+                        match shape_processor.process(&evaluation.shape) {
+                            Ok(shape) => {
+                                viewer.handle_shape_update(shape);
+                            }
+                            Err(err) => {
+                                // Can be cleaned up, once `Report` is stable:
+                                // https://doc.rust-lang.org/std/error/struct.Report.html
 
-            match event {
-                ModelEvent::Evaluation(evaluation) => {
-                    status.update_status(&format!(
-                        "Model compiled successfully in {}!",
-                        evaluation.compile_time
-                    ));
+                                println!("Shape processing error: {}", err);
 
-                    match shape_processor.process(&evaluation.shape) {
-                        Ok(shape) => {
-                            viewer.handle_shape_update(shape);
+                                let mut current_err = &err as &dyn error::Error;
+                                while let Some(err) = current_err.source() {
+                                    println!();
+                                    println!("Caused by:");
+                                    println!("    {}", err);
+
+                                    current_err = err;
+                                }
+                            }
                         }
-                        Err(err) => {
-                            // Can be cleaned up, once `Report` is stable:
-                            // https://doc.rust-lang.org/std/error/struct.Report.html
+                    }
 
-                            println!("Shape processing error: {}", err);
+                    ModelEvent::Error(err) => {
+                        // Can be cleaned up, once `Report` is stable:
+                        // https://doc.rust-lang.org/std/error/struct.Report.html
 
-                            let mut current_err = &err as &dyn error::Error;
-                            while let Some(err) = current_err.source() {
-                                println!();
-                                println!("Caused by:");
-                                println!("    {}", err);
+                        println!("Error receiving updated shape: {}", err);
 
-                                current_err = err;
-                            }
+                        let mut current_err = &err as &dyn error::Error;
+                        while let Some(err) = current_err.source() {
+                            println!();
+                            println!("Caused by:");
+                            println!("    {}", err);
+
+                            current_err = err;
                         }
                     }
                 }
-                ModelEvent::Error(err) => {
-                    status.update_status(&err.to_string());
-                }
             }
         }