Graphics issue or bad UVs (Mudbox)

Stu2Prof

Hello,

I am seeing painting artifacts when I import my model into Mudbox 2014 and wanted to know how I could stop them. I have researched a little bit and found someone suggesting it could be a graphics driver issue while others say that it is a question of bad UVs. I would really appreciate your help in finding the source of this problem and your suggestions to how I could fix this. I'm still an early learner so don't know how to judge if my UVs are good enough quality.

images below:





Other forum posts:
http://forums.cgsociety.org/showthread.php?f=221&t=885366
http://www.polycount.com/forum/showthread.php?p=1989054#post1989054

.Wiki

Check your UV Seams. It looks like the polys are flipped in your UV set.

tadpole3159

try painting on a 16 bit texture instead of an 8 bit one

oglu

or the uvs are disconnected... sometimes this happens during export...

Stu2Prof

Thank you for your responses. I have attempted a 16 bit texture but that didnt seem to fix the problem.

@Wiki What are the signs of flipped UVs? I tested out the model with a numbered checker texture but didn't see any flipped numbers on the model itself. Is this the correct way of testing flipped UVs

@oglu thank you for the suggestion oglu. How would I be able to see this problem in Maya and also what can I do to fix the problem?

Apologies for asking questions that may seem a bit basic but I have been trying to do my own research before posting again and have been finding it difficult to find an answer.

Thank you guys for your help

.Wiki

Yeah I meant the same as Oglu I just didn´t explained it the correct way I guess

I had this recently when I exported to mari. Each UV Polygon was disconnected and flipped 180°. This happened to me when I used the OBJ exporter.

Stu2Prof

Okay I just did a test on one of the default mudbox models and got the same problem again. Does this mean I have a problem with my graphics card? It appears the most prominent when I am lightly pressing on my wacom pen

MM

it is a mudbox2014 bug and not related to hardware as far as i have seen. the faster your brush strokes the more artifacts you will get. you can try openEXR 32bit format for slightly better painting but there will still be issues when your paint strokes are fast.

i have autodesk certified/recommended FireGL card, can sculpt on 100mil polygons without lag AND i still got the same issue as above.
one of the many reasons i didnt upgrade. 2011 works much better for painting.

Stu2Prof

Thanks MM, I have a Firepro V5900 so I was also surprised to have problems that are apparantly caused by unsuitable graphics card drivers.
While researching the problem I found another possible route for solving the issue which involves adding the environment variable "MUDBOX_PAINT_CONTEXT_FLUSH" to flush the paint cache inbetween strokes.
I would like to try this because I do not own a copy of mudbox 2011 but am unsure what information to put into the windows control panel. Could someone assist me? (definitely getting out of my depth)

Edit- Just checked the Mudbox 2014 Service Pack 2 page and it suggests using this environment variable. "With AMD graphics cards, if you are seeing texture painting corruption such as painting black and artifacts adding the environment variable "MUDBOX_PAINT_CONTEXT_FLUSH" may fix the problem."

MM

give it a shot.

from what it looks like the variable name is "MUDBOX_PAINT_CONTEXT_FLUSH" and variable value should be "1" if it is an on and off thing.

but i doubt this is a texture cache issue. please let me know if it works.

Stu2Prof

.....Nope. Just made my wacom, keyboard and 3d mouse take a really long time to be recognised by the computer.....

Stu2Prof

Update: I recently messed around with the Paintbrush again and managed to paint without any artifacts. What seemed to have fixed it was unchecking "Stamp Spacing". It also works fine if I check stamp spacing and use a stamp image thats not the default Mudbox brush

unit187

Heh, I had the same problem and couldn't find a solution. So I have switched to 3dcoat and in fact it is even better than Mudbox overall.

Stu2Prof

Definitely feeling some disappointment in Mudbox's performance. I have been actively learning for 2-3 months(including investing into a new machine) in order to create some 3d artwork for my portfolio and these technical problems/bugs have been a deterrent.

unit187

I don't know about other aspects of 3dcoat (means sculpting, retopo...), but, seriously, give it a try for 3d painting.
I had a number of problems with mudbox (artifacts like in the thread, "missing" projection because of too low-poly mesh, layers blending that gives different results when in Photoshop and when in Mudbox, etc...). I wouldn't work with such unpredictable software in production environment. Haven't encountered anything like that in 3dcoat so far.

And also 3dcoat costs less than Mudbox, which is nice