URGENT Marmoset Rendering error

lymiller

I'm in Marmoset trying to render out my model, and I keep getting these strange artifacts on my model. I have to finish this today, and I don't understand what is going on.

Please help!

Snader

I'm not acquainted with Marmoset, but my guess is that those grey polies are 'inside out'. Try flipping the normals on them?

lymiller

If I flip the normals on the eyeball in 3DS Max, and reimport it into Marmoset, it doesn't show up (backface culling on). For some reason those areas are just showing up brighter, but their normals seem fine.

This is due today, so I'm really anxious to get it figured out.

NinthJake

I'm not familiar with marmoset so I'm just throwing out suggestions from the top of my head.

Are those UV seams?
Have they accidentally been moved to another smoothing group?
Did you export the mesh as triangles?
EDIT: Also have you checked with a texture applied?

konstruct

could be:

+vertex colors
+flipped normals
+split edges/verts/polys that share the same space
+material IDs
+smoothing groups
+zero face polygons

Try dropping an "STL check" modifier. Its sort of an old school way of hunting down broken stuff on your model.

lymiller

NinthJake:

(1) They aren't UV seams, but for some reason when ZBrush exports an OBJ with the Multi Map Exporter every polygon in the UVs become a seperate shell. I'm not sure if this is causing the issue since I have reimported UVs and switched the original OBJ from Max several times now -- same problem. It seems to be a problem with the mesh itself that only Marmoset is having an issue with.

(2) I made sure to unify all smoothing groups -- still the same.

(3) Yes, I tried that, too, just now. It looks exactly the same.

(4) Here was an earlier version of the model before I had to redo the topology/UVs: http://www.polycount.com/forum/showpost.php?p=1430104&postcount=14 In that case I'd solved the problem by switching in the OBJ that ZBrush exported.

Lucas Annunziata

I too have been getting some artifacting with marmoset on a couple different models recently. I've gone through the list of usual suspects that have been suggested and had no such luck.

lymiller

konstruct:

Yeah, I used STL check and everything is fine. I'll try the material IDs and such and see if that works. I'll get back to you.

tigg

Check for polies that havent been uvmapped properly. This happened to me once, it turned out I'd hidden a small triangle whilst uvmapping, and never actually mapped it. For some reason this throws the lighting off on a whole bunch of other polies too.

lymiller

Okay, I'll try fixing the UVs again. Sigh. lol I have a suspicion that something might've happened -- I'll see if I'm right.

Thanks so much, everyone! I'll get back to you.

lymiller

So, I dunno about you guys, but this is probably part of the reason:



I don't know why it's creating those green seams INSIDE of the shells (that there is his back leg, which is one of the culprits) but it is probably a side effect of redoing the UVs and topology several times. O_o Hopefully this fixes the problem!

Visceral

I have had this issue. Make sure that:

Faces are triangulated
Exporter is working

I had some problems with basic OBJ export form Maya 2011 to Marmoset that resultet in this issue. I think triangulation solved it. Cant remember since i was in total panic mode.

konstruct

AH- thats your problem right there. get rid of those seams on your UV`s. Whats happening is because its a broken UV- its also a break in the normal tangency.

get rid of all those UV seams and you *should* be golden.

Sadly- you might have to re-bake your normals, as normal tangency is a pretty big deal when baking out a normal map :P

heres sorta what Im talking about:


1 smoothing group creates merged normal tangents- 2 smoothing groups creates a break in your normal calculation.

UV seams do the exact same thing to normal tangency- as a break in the smoothing groups, or a seperation in the actual geometry. Its all the same crap at the end of the day :P

lymiller

Yeah, I just confirmed that that was the issue. Good to know!

Yeah, I knew I'd have to rebake everything -- it's fine. I actually had my UVs too closely packed, and the "bleed" that ZBrush was creating on each shell were overlapping with each other. :x

Thanks, everyone! I'm so glad this problem was solved.

Dylan Brady

this is similar to my problem that I have been trying to troubleshoot for the last few days.
I've posted some images on the Marmoset thread.
http://www.polycount.com/forum/showthread.php?t=74848&page=31
But my issues differs in that I can't find any unwelded verts in the UV map.
and if you scroll down on that post, you'll notice that 80% of my verts have 3x as many tangents/bitangents as should be there.

Edit: I just whipped out STL check and found no errors

SiegePerilous

Marmo also wasn't liking my mirrored texture and was going all to hell down the middle of the model, though in max it looked fine.

Also found out from earlier problems that Edit Normals modifier in Max is amazing (so far...waits for explosion), and that Normals modifier works on specific selected polygons, so don't expect to just click Unify Normals and have it unify all normals on your model (that would be WAY too easy).

good luck my friend.

Dylan Brady

thnks, I figured it out. It was my Export.
I finally just messed around with the FBX export options until it worked.
Turns out it you want to have tangents and binormals that are correct DONT check the tangents and binormals checkbox