[TRACKER] GodotPhysics 3D issues

[pouleyKetchoupp]

This tracker is for all physics issues that affect Godot Physics 3D.

Note 1: Issues that are reported on both 2D and 3D are listed here and in #45334.

Note 2: Issues that can be reproduced on both Bullet and Godot Physics are listed here. Bullet-specific issues are listed in #45022.

Note 3: Issues related to features that are currently Bullet-only are listed here when the plan is to implement them in Godot Physics too (soft body, heightmap).

RigidBody

• Unstable RigidBody when adding/applying forces/torque #25468
• apply_impulse, add_force sometimes makes the RigidBody fly away. #36703
• Rigidbody doesn't rotate when linear movement restriction on all axis is applied #36847
• Setting RigidBody global_transform into the _input function fails. #40486
• RigidBody box collision shape failing collision detection through convex and concave shapes when impulse is applied, on Bullet #41404
• Low speed RigidBody overlaps StaticBody then bounces back when collision happens even with CCD enabled and 0 bounce #43605
• (Godot Physics) Rigid-to-Rigid body collisions penetrate each other #46655
• RigidBody gets stuck on collision boundaries #46712
• [GodotPhysics] Thin collision shapes cause resting RigidBodies to shake at low physics FPS #62819
• PhysicsServer error with rigid BodySetSpace() GodotPhysics #46738
• RigidBody gains momentum with each collision when bounce = 1 (both 2D and 3D, Bullet and GodotPhysics) #52550
• [GodotPhysics] Thin RigidDynamicBody3D oscillates and doesn't settle in simple box-box collisions #61827

KinematicBody/CharacterBody

• KinematicBody/2D uses any combination of layer-mask for move_* collision detection #15243
• 3D KinematicBody slides with move_and_collide #18433
• Move_and_slide_with_snap steep slops problem #30310
• Move_and_slide_with_snap fails to follow a moving platform if stop_on_slope is set to true #30311
• KinematicBody still able to move Rigidbodies and VehicleBodies when infinite inertia disabled #31981
• KinematicBody player with RayShape does not respect snap argument in move_and_slide_with_snap() #34098
• RayShapes in 3D sometimes causes player to vibrate in place #34663
• [GodotPhysics] KinematicBody3D with move_and_slide() move bumpy/jittering on flat surface #45060
• move_and_slide caches physics values between frames #46603
• move_and_slide uses instaneous velocity on rotating platforms resulting in drift #46604
• Collision detection between moving kinematic and rigid bodies is broken #46653
• RigidBody pushes KinematicBody in 3D Godot physics #49203
• [GodotPhysics] KinematicBody jitters against floor #49323
• Discussion of CharacterBody behavior #50732
• When jumping on a horizontal-moving slope, the landing point will be shifted #53435
• Cylinder shape collision issues with GodotPhysics #57048
• Godot 4 - choppy movement when sliding one object around another #66917

Smooth steps

• Godot 3.2.3 move_and_slide_with_snap() doesn't function correctly at 144fps.  #43368

Collision detection

• RigidBody and RigidBody2D ignore scaling on runtime #5734
• 3D KinematicBody is not correctly detecting collision with PlaneShape #5910
• Inaccurate physics with simple bodies (RigidBodies can temporarily penetrate other PhysicsBodies) #16505
• Scale or Rotate RigidBody should be locked, not just alerted #26890
• Godot physics performance issue when colliding with a ConvexPolygonShape generated from a SphereMesh #26906
• KinematicBody does not collide with new position of a moved KinematicBody - can tunnel through #30481
• RigidBody sometimes misses reporting a contact #37308
• Collision detection issues - multiple collision shapes, CCD #39095
• Rotation/Scale/Translation mixes on CollisionShapes not consistently resulting in correct collision #41685
• Insufficient processing of RigidBody in the physics engine (Bullet and Godot) #45182
• [Godot Physics] Cylinder-Cylinder collision issues with move_and_slide() #47094
• [Godot Physics] Box-Cylinder collision issues with move_and_slide() #47095
• [Godot Physics] ConvexPolygonShape-Cylinder collision issues with move_and_slide() #47096
• [Godot Physics] Capsule-Cylinder collision with move_and_slide sometimes gets bad collision normals #47185
• GodotPhysics CSGBox collision halting momentum (using CylinderShape) #48142
• CharacterBody3D exhibits very poor performance against certain concave colliders. #50300
• 3D rotating/spinning RigidBody bumpy collisions with Trimesh Static Body #50463
• Collision exclusion doesn't work when bodies are already colliding #50527
• KinematicCollision much less accurate in GodotPhysics compared to Bullet #52384
• RigidBody with CylinderShape jiggles by itself on Plane #52542
• [GodotPhysics] VehicleBody3D (RigidBody) collision with static mesh cases sub zero framerate #52888
• [GodotPhysics] Trimesh collision kill my FPS  #59491
• create_multiple_collision_shapes() does not do convex decomposition #67801

Area

• Changing node parent produces Area2D/3D signal duplicates #14578
• Area2D/3D monitoring and monitorable are not working according to docs #27441
• RigidBody in an Area node with gravity point increases it's speed continuously #30575
• Reparenting node in Area.body_entered causes crash #34207
• area_entered and area_exited emitted multiple times while still overlapping #35595
• Raycast can collide with area even if monitorable property is set to false #41155

Joints

• Joints slide #31864
• Generic6DOFJoint is behaving in a weird manner when rotating around the Y axis (it's working properly for the Z axis) #33083
• [Bullet] Angular limits in Generic6DOFJoint doesn't work #33707
• Physics. Joints. Motor. #34398
• HingeJoints stop working when the scene containing them is reparented #41398
• [Godot Physics] Creating a joint between two kinematic bodies results in cryptic error message #47478

Raycasting

• PhysicsDirectSpaceState intersect_ray exclude does not work with GridMaps #27282
• Intersect ray hit RID is different each time? #36824
• SpringArm(3D) can tunnel into objects with Godot physics but doesn't with Bullet #47093
• Raycast Not Detecting CollisionShape3D: ConvexPolygonShape3D Mouse Collision in v4.0 #47483
• PhysicsDirectSpaceState.intersect_ray returns a different result with Bullet and GodotPhysics #49055
• [Bullet] RayCast collision noise near edge of static body #49163

GridMap

• Collision section of GridMap is outdated when compared to TileMap #3284
• Octant physics negatively impact GridMap performance #28801
• Dynamic Gridmap unloading causes physics engine errors and FPS issues #33648
• GridMap reports errors to the Physic server on removing cells #43712
• world_to_map() returns inconsistent values when using raycast #46561

CSG

• CSGShape use_collision doesn't use collision layers and masks #22246
• Collision between CSGPolygon and ConcavePolygonShape not working #30442
• CSGShape doesn't have physics material #36893
• Broken collision with invisible CSGCombiners #43251

Ragdoll

• Move joint does not work #26618
• ragdoll simulation twitches in simple humanoid ragdoll #28707
• PhysicalBones do not move with skeleton when simulation is off #40076
• PhysicalBones break after saving and reloading the scene #40549
• Scaling Skeleton with PhysicalBones results in math errors #40614
• Having BoneAttachment node before a Physical Bone for the same bone throws error #42010
• PhysicalBone is delayed if it has not ragdolled parent #44589
• [Bullet] Ragdoll (physical bones) spazz out if they were affected by IK before #46816
• Removing PhysicalBone from active ragdoll freezes attached vertices. #49193
• Node with physical bones spams rotref_posscale_decomposition: Condition "!m.is_diagonal()" error when it's added to or removed from scene #49202
• Physical Bones that aren't simulating don't get detected by RayCasts #51929
• [GodotPhysics] Ragdoll / PhysicalBone don't work on scaled models with Godot Physics #52971
• Ragdoll / Physical bone doesn't work with overlapping collision shapes on Godot Physics #52972
• "Generate physical skeleton" creates wrong bone positions #53466
• root motion movement is wrong if skeleton has added physics bone  #53919

SoftBody

• Weird behaviours with soft body node under kinematic parent #21190
• softbody mesh got stucked ? #22160
• Setting SoftBody pinned points programmatically #26594
• SoftBody pinned point indices not corresponding to mesh vertices due to removal of duplicate mesh vertices #26611
• Soft bodies do not collide with each other #27039
• vulkan - 4.0 dev - SoftBodies are broken #33485
• SoftBody is not affected by space override #36693
• Softbodies do not work when run in headless mode. #37125
• SoftBody doesn't follow the fixed point in real time. #41194
• SoftBody shoots from point zero [GLES2] #41390
• SoftBody It has error get_global_transform #42487
• SoftBody ignores translation when using GLES2 #44883
• Incorrect face area for soft body 3D #47962
• SoftBody simulation running with bad performance with medium-high dense meshes #52990
• Softbody simulation misses a lot of collisions #52991
• Vulkan: SoftBody3D is incorrectly culled due to its visibility AABB not being updated #52992

VehicleBody

• VehicleWheel sinks into other colliders #45339
• VehicleBody behaves weirdly with CollisionPolygon #34567
• [Bullet] Wrong physics when accelerating and braking using VehicleWheel #34856
• Vehicle Instance is broken (nan error) #35877
• Vehicle Wheel doesnt spin on air #37018
• godot 3.2 VehicleBody and VehicleWheel engine_force strange behavior #37816
• VehicleBody not react to collision layers #42253
• Rotated VehicleWheel spins in the wrong direction #47650
• [GodotPhysics] VehicleBody3D (RigidBody) collision with static mesh cases sub zero framerate #52888

Heightmap

• HeightMapShape collision does not update properly when the body is translated #37337
• Cannot create a HeightMap CollisionShape in Godot physics. #40664
• HeightmapShape gets KinematicBody stuck, unlike BoxShape or ConcavePolygonShape #43625

Multi-threading

• ARVR image shakes when Multithreaded and ARVROrigin is attached to RigidBody #26900

Other

• Inconsistent physics delta #31016
• Procedural Generation for Android app #34000
• 3.2 Bug - NAN Error randomly spams console, then crashes #35913
• Window freezes when using PhysicsServer in background thread #37850
• [Bullet] Performance issues when adding lot of convex shapes to a RigidBody #41076
• GodotPhysics performance when interacting with servers directly #45360
• Executing RigidBody.new()._direct_state_changed(BoxShape.new()) crashes Godot #46003
• PhysicsServer3D errors when starting new project #46167
• Executing RigidBody3D.get_inverse_inertia_tensor() crashes Godot #46282
• Adding shapes and bodies from the PhysicsServer doesn't work in C# #46600
• Crash when adding, moving and removing 3D physics nodes with collision shapes in Godot physics #47438
• Make Godot Physics 3D constraint solving more deterministic #48303
• Single and Multiple Collision Siblings issues #48468
• Kinematic/Character bodies cause slowdown/crash when colliding with convex collision shapes #48587
• SpringArm Node Bug: Spring Arm ignores collision when 'spring_length' is being updated #48990
• CharacterBody3D / Garbage Collector Memory Leak  #53172

Editor

• Collision layer name doesn't update in the inspector when changed #29991
• CylinderShape and HeightMapShape GodotPhysics error on project startup (due to EditorHelp generation) #32216
• Discrepancy between physics joints behavior and editor gizmo #40885
• Debugger RayCast Reference Crash segfault in ::_get_property_listv #40962
• Creating convex collision from a mesh results in duplicate vertices #41522
• When raycasting in editor (Tool), collisions only register within bodies' original bounding box area (fixed in master) #43744
• Lag spike when creating collision shape for mesh instance #44090
• QuickHull generates bad hull sometimes when multiple triangles share the same plane. #45946

Documentation

• Joints spring settings #34395
• Instancing of a scene does not instance a new ConcavePolygonShape in a collision shape #40887
• RigidBody freezes in rotating Spatial #45268
• Physics documentation should teach users to set parameters before adding nodes #45638
• [Bullet] collide_shape returns unintuitive/wrong values #45680
• Pause mode enabled stops body/area signals being raised on a scene that has pause mode set as Process #47326
• PhysicsMaterial needs better documentation for friction and bounce #48461
• Mouse click (input_event) is not processed for a CollisionShape inside another CollisionShape #50701
• Document how collision layers work in VehicleBody3D #52983

4.0 refactoring

• body_test_motion not available in gdscript on PhysicsServer #20276
• apply_impulse is not intuitive #21634
• Shouldn't PhysicsMaterial properties correspond to individual shapes rather than the body? #25254
• move_and_slide() takes in velocity, while move_and_collide() takes in position offset #30029
• Multi camera 3d setup doesn't update collision shapes translation properly #52345

[Demindiro]

I think #35877 should be added here too?

[josefkaragoli]

Will you completely rewrite godotphysics from scratch or just address the issues in the tracker?

[Calinou]

Will you completely rewrite godotphysics from scratch or just address the issues in the tracker?

I don't think it'll be rewritten completely, even if parts of GodotPhysics may receive a refactoring. Instead, issues will be fixed individually.

[golddotasksquestions]

Is it possible to add these two issues as well?
#14578
#27441

[pouleyKetchoupp]

@golddotasksquestions They are already in the 2D physics tracker.

[josefkaragoli]

Is there a repo or somewhere we can see progress?

[Calinou]

Is there a repo or somewhere we can see progress?

Progress on the physics engine itself occurs on this very repository. Look at pull requests labelled with topic:physics: https://github.com/godotengine/godot/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc+label%3Atopic%3Aphysics

[Saitodepaula]

I know it is not an issue, it is a proposal, but could this one be included too?
godotengine/godot-proposals#945

My point is that I want to transition my game from Bullet to Godot Physics. There were only 2 things preventing me from doing that: cylinder shapes and center of mass of a rigid body. Now, it's only the position of the rigid body. If I can't change it, I can't move my game to Godot Physics, and I thing there are other games in the same situation.

As a side question/note: is it documented that Godot Physics handles center of mass in a different way than Bullet? I've read it somewhere, but can't find it now: that Godot Physics takes all the collision shapes of a body and calculates the center of mass from them. It is right there in the rigid body doc... Sorry for that...

[Calinou]

As a side question/note: is it documented that Godot Physics handles center of mass in a different way than Bullet? I've read it somewhere, but can't find it now: that Godot Physics takes all the collision shapes of a body and calculates the center of mass from them.

Yes 🙂

Perhaps this could be added to the manual as well, but I'm not sure which page this information should be added on.

[Einlander]

Can #46610 be added to the csg section?

[Calinou]

Can #46610 be added to the csg section?

This isn't a physics-related issue. It seems we don't have a dedicated CSG tracker issue yet, but feel free to create one if you can accumulate links to current CSG issues.

[snouk-z]

Can this one be added to ?
godotengine/godot-proposals#483

Enabling calls to the physics API from multiple threads would be an awesome addition.

[RabidTunes]

@golddotasksquestions commented on 20 Feb
Is it possible to add these two issues as well?
#14578
#27441

@pouleyKetchoupp commented on 20 Feb
They are already in the 2D physics tracker.

As I pointed out in one of #14578 comments, this also happens in 3D with the correspondent 3D nodes. Maybe should I create another separated issue for 3D?

[pouleyKetchoupp]

@RabidTunes I've added them to the 3D tracker.

[lewis-conroy]

Sorry if this already exists, but KinematicBodies moved with move_and_slide() slide down slopes regardless of the value of stop_on_slope. Is there an issue open for this already?

[Calinou]

Sorry if this already exists, but KinematicBodies moved with move_and_slide() slide down slopes regardless of the value of stop_on_slope. Is there an issue open for this already?

Yes: #31097

[Nekuromu]

I have opened another issue on ConvexPolys related to RigidBodies floating #55503

[timshannon]

FWIW, @elvisish I think there are a lot of bugs with the cylinder implementation and maybe capsule. All of my getting stuck with my character body issues went away with a cube collision shape. It's not ideal, but it works better than a cylinder.

[elvisish]

FWIW, @elvisish I think there are a lot of bugs with the cylinder implementation and maybe capsule. All of my getting stuck with my character body issues went away with a cube collision shape. It's not ideal, but it works better than a cylinder.

Thanks, I was using capsule as I want to go over some rocky terrain but... Godot 4.0 still doesn't have stair stepping, hmm.

[Saitodepaula]

It seems to me a strange allocation of resources to see all these updates on new 3D rendering techniques while it looks like the fundamental ability to move around in 3D environments is so unreliable.

Are there plans to re-aquire a dedicated physics contributor or is that not a priority?

I have been using Godot for 3 years now, developing a game, opening some issues, watching development in many areas, and even created open source demos for physics based games. I've never complained about some features in the physics area progressing slowly (or not progressing at all), because I understand that, this being FOSS, that's how it works: if there are capable people wanting to do something, it gets done. If there are no people, nothing happens.

But now that Godot 4 is in beta 3, rendering seems to be evolving well, subjects like double precisions for large worlds getting an exclusive blog post (a subject I would think only a few games would need), wouldn't it be nice to have a roadmap of where physics is intended to go?

I'm not even asking for development in this area, because this is FOSS. But some information about what the project leaders think is the most probable route from now on. Just a few examples: vehicle body, is it going to stay? Joints in general, are they going to be fixed?

[qdeanc]

Just some context:

The Godot team had initially hired a skilled contributor who was seemingly going to fix all of these bugs, but that person ended up accepting a job working on the Rockstar Games physics engine as far as I'm aware.

As far as I know, collision detection (especially continuous collision detection) and stable collision/constraint solvers are especially complicated to program. It's probably hard to find another specialist willing to take on such a challenge remotely and for an affordable rate.

[elvisish]

I think our only hope in the immediate future is for PhysX or Rapier or something to be ported as an extension to provide something extremely stable that, while perhaps not as well integrated or optimised for game work as GP, would at least be fail safe for production work until GP is 100% reliable in all conditions.

[timshannon]

I think our only hope in the immediate future is for PhysX or Rapier or something to be ported ...

I'm keeping my eye on https://github.com/jrouwe/JoltPhysics personally. I'm hoping GDExtension opens up a lot of possibilities.

[golddotasksquestions]

@timshannon @elvisish
Regarding JoltPysics there is a discussion regarding Godot integration here: godotengine/godot-proposals#5161

[elvisish]

Quick reminder that this minimal test project I uploaded a year ago-ish is all you need to test if physics are working or not; if it goes up stairs while crouching or doesn't get stuck behind the stairs, we done: #58260

[alfredbaudisch]

Should I create bug report for this or is there already something related?

Colliding against ConcaveShapes or ConvexHulls with move_and_slide with a very simple CharacterBody3D controller makes everything sloppy or frozen from 10ms to 2 seconds.

Notice how the game just freezes when hitting the barrel:

MoveAndSlideSlow.mp4

[Zireael07]

@alfredbaudisch How complex is that collider on the barrel? Because that looks like #48587

[alfredbaudisch]

@alfredbaudisch How complex is that collider on the barrel?

I attached the image of the wireframe, the collider is closer to the mesh structure, it's around 700 vertices, which should not cause this kind of slow-down.

[alfredbaudisch]

@Zireael07 it's indeed related to #48587 and #66354 and #57313

[GrauBlitz]

I am a bit shocked to see a v4 RC1 with all this open issues, meanwhile my Bean Character still get's stuck on the edge of an cube...

[Lippanon]

There will definitely be more focus on bug fixing after beta.

Since this comment, 3 more issues were added to the tracker, 0 were checked as fixed, and a bunch more physics-related were created that aren't in the tracker. There's an ever increasing issue list, with multiple regressions from betas that don't get fixed before new versions get pushed. I appreciate that Godot relies on willing contributors but why are Release Candidates already being put out? Is there a deadline? It feels like Godot 4 is being rushed for no good reason.

[akien-mga]

A lot of physics issues have been fixed in past weeks. This tracker isn't necessarily up to date.

And yes, a lot of issues remain, and they will be fixed after the 4.0 release. We can't block everything waiting for the current WIP physics fixes to be merged. We stabilize what we have now and which is already usable by many, and we'll fix more issues in 4.1.

[elvisish]

stabilize what we have now and which is already usable by many

I'm just not sure Godot Physics are currently usable (for production work), prototypal maybe.

[Calinou]

I am a bit shocked to see a v4 RC1 with all this open issues, meanwhile my Bean Character still get's stuck on the edge of an cube...

Box colliders tend to be a lot more reliable than capsules currently. I recommend sticking to a box collider (and make sure it's not rotated during gameplay).

I have a box collider-based FPS controller in https://github.com/Calinou/godot-demo-projects/tree/add-first-person-shooter and it's working quite reliably overall.

[Saul2022]

And yes, a lot of issues remain, and they will be fixed after the 4.0 release. We can't block everything waiting for the current WIP physics fixes to be merged. We stabilize what we have now and which is already usable by many, and we'll fix more issues in 4.1.

While i understand it, i think it not quite usable rn,especially on 3d , many users have reported it and i think a better solution would be reimplementing bullet, atleast as a gdextension if there’s time.

[elvisish]

Box colliders tend to be a lot more reliable than capsules currently. I recommend sticking to a box collider (and make sure it's not rotated during gameplay).

This is very true, and I've exclusively used box colliders that don't rotate (AABB, basically) using a child gimbal that's rotated to determine direction of movement. However, the engine is still plagued with issues using a box collider; as far as I'm aware it's still impossible to walk into an angled corridor or into a sloped ceiling that becomes thinner or shorter than the collider without irreparably getting stuck and having to reload the scene.

[GrauBlitz]

Box colliders tend to be a lot more reliable than capsules currently. I recommend sticking to a box collider (and make sure it's not rotated during gameplay).

This is very true, and I've exclusively used box colliders that don't rotate (AABB, basically) using a child gimbal that's rotated to determine direction of movement. However, the engine is still plagued with issues using a box collider; as far as I'm aware it's still impossible to walk into an angled corridor or into a sloped ceiling that becomes thinner or shorter than the collider without irreparably getting stuck and having to reload the scene.

But switching to a box collider should not be necessary for a fully v4 imho, as a capsule collider is a typical Character Controller shaped and recommended in every tutorial, especially for the Unity folk which is watching this engine to switch on v4. Releasing with an instable physics engine could leave many people behind or scare them away.

I am still experiencing many issues, my character controller is getting stuck on any a bit steep angle, independent from the collision shape. I can't walk normally on a procedural generated terrain, i can't walk or jump over a cube without issues, ... i think these are very basic Physic engine usecases and nothing special.

[Zireael07]

But switching to a box collider should not be necessary for a fully v4 imho

True, but unfortunately "fully v4" won't be what 4.0 is. 4.0 has already been in the works for so long and trying to iron out all the bugs would only delay it by another three months or more IMHO - which is not worth it.

Releasing with an instable physics engine could leave many people behind or scare them away.

Physics have had issues back in 3.x too (actually, most of the problems in the tracker exist in 3.x too). Somehow that didn't scare people away from using 3.x

[elvisish]

my character controller is getting stuck on any a bit steep angle, independent from the collision shape. I can't walk normally on a procedural generated terrain, i can't walk or jump over a cube without issues

I don't think you can use anything but boxes for floors right now, slightly sloped boxes might work but it can't change shape over the shape like terrain would or you'll get stuck.

[elvisish]

True, but unfortunately "fully v4" won't be what 4.0 is. 4.0 has already been in the works for so long and trying to iron out all the bugs would only delay it by another three months or more IMHO - which is not worth it.

If a major (and physics is major) component is completely broken, what is the purpose of releasing 4.0? It's just a number, and there's no shareholders or investors to please so it makes no sense to rush release something that isn't ready yet.

Physics have had issues back in 3.x too (actually, most of the problems in the tracker exist in 3.x too). Somehow that didn't scare people away from using 3.x

Besides the complacency of this, nobody uses Godot Physics in 3.x as it's broken, they use Bullet which isn't broken and was removed in 4.0 (for no particular reason).

[GrauBlitz]

But switching to a box collider should not be necessary for a fully v4 imho

True, but unfortunately "fully v4" won't be what 4.0 is. 4.0 has already been in the works for so long and trying to iron out all the bugs would only delay it by another three months or more IMHO - which is not worth it.

Releasing with an instable physics engine could leave many people behind or scare them away.

Physics have had issues back in 3.x too (actually, most of the problems in the tracker exist in 3.x too). Somehow that didn't scare people away from using 3.x

I never had any issues with v3, but for me 3D development in v4 is plain unusable with the physics and i would not call this "iron out all the bugs" but more like providing a basic feature set of physics. Maybe I'm just not competent enough to setup a simple Character Controller with the v4 templates but I will have to skip v4 and wait for the next versions so i don't understand why releasing v4 in this state is even an option.

[akien-mga]

So I already answered all this here:

#45333 (comment)

This discussion is going nowhere, so locking. This is a tracker to keep an overview of bug reports, not to rant about Godot's release policy.

We're doing what we can, most other areas are release ready and while physics still has significant known issues, it's not the end of the world and they will be worked on and fixed in future 4.x releases. If you're making a physics based game that can't work in 4.0, you can simply skip this release and wait for a future 4.x release which will fix your issues - but there's no reason to hold the release for the many other use cases which work fine.