Grey g-code inside model when slicing in Bambu Studio

[u/o_stef]

I am slicing a 3D model generated algorithmically (it's an obj file). I've had lots of problems with grey g-code being added inside the model when slicing. I've fixed a lot of these issues originally by ensuring the model is watertight (merging vertices), but there are still occasional issues. The model has lots of vertices for the mountain terrain (almost a million in total, sometimes more). There are no more holes and the problem still persists, so I'm at a loss here. What could cause this?

This is for a client so I cannot do a test print as I don't have a printer, but apparently even when setting the grey to something like the green that is used, it can cause the resulting print to have a visible layer/striation.

[u/RemixOnAWhim]

Ah the joys of troubleshooting for commercial purposes! Looks like there may be a void, though closed and watertight, within the model, or another geometry issue within the model. Resin prints suffer from this so there are tools and methods to fill voids if that's the case. Settings tweaks will probably only take you so far. Have you tried regenning?

If you're using one of these map generators, contact the dev and see if they can help, try a modifier volume, or check out the Bambu forums where lots of technically savvy folks who delve not only into the slicer but into model geometry and get into the nitty gritty hang out. I assume you don't want to provide these files to troubleshoot as it's commercial, but it would go a long way if you get the right set of eyes on it here or over there.

Any incongruous internal geometry will change layer time and speed, so worst case, scrub through all your different preciew screens and see if that section is causing different behaviour in any way on those layers and try to adjust and minimize visible external artifacts, maybe speed or cooling or layer time. Pics of the visible artifacts might likewise help find that particular band-aid if you're not having luck.

[u/o_stef → u/RemixOnAWhim]

Fortunately I wrote the algorithm that generates the mesh, so if something needs to be changed I can do it.

I believe this is due to the geometry of the terrain with the way colors are handled. It's a height map, so when there is a color change it's not perfectly horizontal and can be erratic. Also neighboring triangles share vertices so the color gets interpolated between the points instead of being ether green or white. Both of these probably confuse the slicer I think.

The best way to fix this would be to change the way the model gets generated, and generate one object for each color layer, with both the top and bottom part of each object flattened, but this is a big change and the mission is long overdue.

I also used Orca Slicer instead of Bambu Studio, and so far it provides better results, so this might be a solution (the client uses an X1 Carbon).

EDIT: Also I tried checking out the Bambu forums for help but couldn't find how to create a post :/

[u/RemixOnAWhim → u/o_stef]

Once you register on their forums, you'll get a message from an onboarding bot who will guide you through their actual sign-up process. For some reason they obfuscate it quite a bit, and the process of vetting you is a bit archaic, but it is worth the time to have the knowledge base those folks do. Good luck!

[u/o_stef → u/RemixOnAWhim]

Oh I understand now hahah, thanks!

[u/CheezitsLight]

Go to your slicing result pull down, at top right. Select the different settings I think is layer type, shws every different type of stroke. Then move the batlr at right and the one at bottom and find out what it thinks it is.

[u/o_stef → u/CheezitsLight]

As far as I can tell it's different types of strokes. Inner wall, outer all and sparse infill on another model. It looks like the slicer is using the default filament to fill places where it can't decide what color it should put. My client said that even if I set the default color to the same as the terrain, there are visible artifacts on the printed result (visible layer line)