Displacement broken edges

[FSGFX]

i deal with a similar problem and its the dispmap itself coming from zbrush...
if you load them as diffuse in mudbox or mari you see the value jump in the texture...

[jstrob]

interesting... I will investigate this

[Morbid Angel]

i deal with a similar problem and its the dispmap itself coming from zbrush...
if you load them as diffuse in mudbox or mari you see the value jump in the texture...

Could it be that zbrush filters the output maps a bit, thus softening the edges?

[FSGFX]

i dont think thats causing the issue...
its more the nature of grayscale dispmaps... how they get stored into the map...
you get those seams if the limit surface and the sculpted one is to much "off"...
its getting better if you use more geo in the base...

if you need a clean displacement you need to use ptex and vector dispmaps... and even there are issues....

[LudvikKoutny]

I don't think displacement should break in any circumstances other than actual physical gaps in the geometry. Meaning if you go into editable mesh edge mode and manually split the edges. If the faces are joined together to create one whole mesh element, then V-Ray should not decide otherwise. It seems that V-Ray displacement unfortunately considers UV map isles as source of geometry continuity information, rather than geometry itself. This ultimately makes it unusable in many production scenarios.

[FSGFX]

It seems that V-Ray displacement unfortunately considers UV map isles as source of geometry continuity information, rather than geometry itself. This ultimately makes it unusable in many production scenarios.

for me it still looks that the baker (zubrush/mudbox) is the issue...

[LudvikKoutny]

for me it still looks that the baker (zubrush/mudbox) is the issue...

Nope, considering that different renderers and 3ds Max native displace modifier handle it without the problem, baker is not an issue. Moreover, the model used here is not output out of any sculpting software, like zbrush or mudbox, it has been modeled inside of 3ds Max, not sculpted. And textures were not painted, just mapped. Not every model comes out of sculpting package, and that should be no issue when handling displacement.

Or to put it in different words, UV seams, no matter how severe, are no reason for continuous geometry to break apart.

[FSGFX]

all render engines (arnold, redshift) render the same seams even if i displace the object with a modifier... its in the texture...
also viewable if i apply the dispmap as diffuse... in my case its the baker...

[LudvikKoutny]

all render engines (arnold, redshift) render the same seams even if i displace the object with a modifier... its in the texture...
also viewable if i apply the dispmap as diffuse... in my case its the baker...

Well, Mental Ray and Corona don't And no, if you apply displacement map as a diffuse, you do see the seam, you see the seam even if you displace, but it does not break continuity of the geometry. Just go back to page 1 of this thread and you will see an example of how it looks in pictures http://forums.chaosgroup.com/showthr...916#post725916

I don't see a point of defending this bug. If it was changed, it would make probably everyone happy. I doubt there's anyone who would willingly want to see holes in their geometry on UV seams.

[FSGFX]

mental ray has the same isues... its the map i bake in zbrush... end of storry...
if you get seam from a 2d non baked image its a bug yes...

and im not taking about a hole in the mesh... im talking about jumps in the surface... the mesh is still closed...

[LudvikKoutny]

and im not taking about a hole in the mesh... im talking about jumps in the surface... the mesh is still closed...

Well, I am talking about the holes in the mesh. That's the entire purpose of this thread That is my main problem.

Obviously, jumps in the surface are expected with seams, and I count on that, but holes are not.

[Mnietek2707]

What about mesh smoothing? Below comparison: displacement on smoothed and unsmoothed mesh.
Broken edges on unsmoothed mesh appear in 2d and 3d mode. Subdivision mode is fine.
2d and 3d mode are also very slow (compiling geometry stage) in vray 3.5
Vray 3.50.04.

[LudvikKoutny]

I haven't tried subdivision mode. You may be onto something, thanks! As for the smoothing group, that was the very first thing I tried, clearing all smoothing group and setting the entire trunk to be 1 smoothing group

[Svetlozar Draganov]

Well, I am talking about the holes in the mesh. That's the entire purpose of this thread That is my main problem.

Obviously, jumps in the surface are expected with seams, and I count on that, but holes are not.

I used the V-Ray scene attached in the earlier posts, converted it to MentalRay and Corona and got the same results - no holes in other engines.
I collected all the data and created a new issue into our bug-tracking system. I'll keep you posted for any updates.

[LudvikKoutny]

Thank you!