ZBrushCentral

Canvas size bug and resulting problems (seams) with creating tileable textures!

Unfortunately, if you try ro create tileable textures in Zbrush the usual way, you’ll run unavoidable into troubles.

So I finally did some exploratory experiments to find out where exactly these problems come from and to show that there are bugs.

For this test I work with a doc size of 100 x 100 cause so the effects could be better seen on the screenshots. But the problems are exactly the same with any resolution.

Okay, let’s go:

First I created a doc in 100 x 100 and filled it with flat white.
And I set the document background color to green and the gradient range to zero. Why, we will see later!

I placed a 45° rotated quad in the middle with 50% flat gray.
Inside I placed a sphere with a white ToyPlastic material.
I did this to show that flat colors won’t be affected by the problems we’ll run into later.

Now we can already see that ZBrushes canvas size is wrong.
Precisely we miss two lines on the top and one line at the bottom.

We export our doc, open it in Photoshop and this confirmes our suspicion.
Here the missing lines are back but unfortunately dark grey (R44,G44,B44) only.

[SS_TTT_100x100_1.jpg]SS_TTT_final_100x100_2.jpg

Okay, we come to the conclusion that we have here two problems.

The first one is, that the canvas don’t show the complete doc content, two lines on the top and one line on the bottom are missing.
But that problem could be by-passed by extending the canvas before export and then cut off the overlapp. But it’s nevertheless a poor mark that this would be necessary and I hope this will be fixed in future versions.

The second bug that causes the artifacts on the edges of the canvas is more serious and I have now idea how to avoid it.

Okay, you could export the doc with some other offsets (before or in this case even totally without enlarging the doc size) and repair the odd parts and seams in Photoshop, but this isn’t a serious workflow and at the moment, it looks like there is no easy way to create 100% clean tileable textures out of Zbrush with this technique. :frowning:

I really hope this gets fixed!

Kind regards,
Tom

Attachments

SS_TTT_100x100_2.jpg

SS_TTT_106x106_1.jpg

SS_TTT_106x106_2.jpg

SS_TTT_final_100x100_1.jpg

I did a few more tests and find out a few things that I want to add here.

The first thing is, that the phenomenon with the to small canvas size (the three missing lines) appear only with the preview renderer but not in best render mode. And with that the "SoftZ" option can even improve the quality under certain circumstances. Best Renderer, Shadows = off, SoftZ = off: [![SS_ZBrush_TTT_100x100_best_1a.jpg|1200x600](upload://zpjY1vScXVyklNT0w70mproGSZq.jpeg)]![SS_ZBrush_TTT_102x102_best_2_PS.jpg|800x640](upload://leHx7HdBM4MlrkR1bTkPV18gdH3.jpeg) As we clearly see there is no benefit for the "color" ;) pass and the normal map is even a lot worse after this procedure. Not just a few artifacts but two complete wrong lines.

Okay, that is if you allocate the normal map shader after the resizing of the canvas! But if you assign it before, the final result will be exactly the same as above without the extra pixel frame. So this adding of additional pixels in ZBrush and external cropping of them later seems to be of no real use at all.

So please, Pixologic, fix these nasty bugs/behaviours.

I beg you!

Kind regards,
Tom

Attachments

SS_ZBrush_TTT_100x100_best_1b.jpg

SS_ZBrush_TTT_100x100_best_2a.jpg

SS_ZBrush_TTT_100x100_best_2b.jpg

SS_ZBrush_TTT_102x102_best_1.jpg

SS_ZBrush_TTT_102x102_best_2.jpg

SS_ZBrush_TTT_100x100_best_1b_PS.jpg

SS_ZBrush_TTT_102x102_best_1_PS.jpg

SS_ZBrush_TTT_100x100_best_2a_PS.jpg

Hi,

Marcus made a “Tileable Texture” plugin as a workaround to create seamless textures and avoid the aforementioned problems.

Thank you very much Marcus, to attend to that limitation! :cool:

Also your plugin shows me, that this bug is now recognized and verified by Pixologic and so I still hope it’ll be fixed in a future ZBrush version and your plugin workaround will then not be necessary any more. :wink:

But till then it’ll be a great help, so thx again.

GRIN!!!
you beat me to it!
That plugin is fantastic, and yes THANK YOU MARCUS!!!

Several years old now but the bug is still there, even in 4R7.
It’s about time to fix that odd behaviour, Pixologic.