Full Soluble Materials interfacing into Models + Soluble material noise on Bed

[MakingThingsWorkToronto]

Version

1.37.2-prusa3d-win64

Operating system type + version

Windows 10 Fall Creators Update

Behavior / Steps to reproduce

Add several Zaribo models to bed: http://zaribo.org/blog/stl/ (see attached STLs below).
Organize parts
Select the "soluble full" preset.
Slice
Preview
Note following issues:

1. Soluble material interfacing into model on bed such that when dissolved there will be holes in the model or overlaps between materials.

https://spgoo-my.sharepoint.com/personal/matt_makingthings_work/_layouts/15/guestaccess.aspx?docid=07426a48f8892440c92004a1390805983&authkey=AdNYg5T0Qg_uDZDjkO3kuTA&e=nNYBK1

2. Soluble material seemingly randomly printed on bed with patterns that interfere with things like brims & potentially other parts.

https://spgoo-my.sharepoint.com/personal/matt_makingthings_work/_layouts/15/guestaccess.aspx?docid=076c62b2bac814f429d6770b1b5232c5b&authkey=AcvzVnS9btj30WQnR4M3vhY&e=pWClc0

I wouldn't expect so much noise on the bed. The more plastic extruded the greater the chances of something going wrong.

I would expect that when a brim is added to parts the soluble material would if necessary be printed on top of the brim.

STL/Config (.ZIP) where problem occurs

Please see above public link to STLs as well as the attached which were optimized for printing.
STL.zip

[bubnikv]

I believe this is a duplicate of #316 , isn't it?

[MakingThingsWorkToronto]

The first part of the bug looks like a duplicate. The noise on bed isn't a big issue but potentially related? I'm cool if this is a duplicate.

[MakingThingsWorkToronto]

Having said that the issue is significant. I've had parts fail because of the support material interfacing into the print. At best it's unreliable & in practice unusable. A bit shocking this functionality is promoted when it is so imperfect.

[bubnikv]

Fixed with fcb714c

Changed the 1st layer infill to rectilinear even for soluble materials.

New parameters raft_first_layer_density and raft_first_layer_expansion
to influence the 1st layer of raft or support.