[Bubblegummonster]

Hello everyone,

I'm trying to render out a character using zbrush. I've created a displacement and applied it in Maya. When I render using Maxwell I can still see the basic outline at the edges. Like for example if you were to just use a bump map or a Normal map. It's not a low res mesh, still around 6000 polys. It's just not stupidly high, which is something I don't want to do as I'll be animating.
Doesn't Maxwell divide the mesh up at all, I know it doesn't tessellate like other renders but it must have to divide the mesh up somehow.

I'm wondering if it's because I'm using a 16bit tiff and not 32bit. I have tried 32 but that seems to really screw up so I decided to stay with 16.

Any ideas


Bubblegummonster

[brodie_geers]

The higher you set the Gain in the displacement settings the more Maxwell subdivides (and the longer the render takes). If you check Adaptive it maxes that out (adaptive is usually a good word in Vray, here it means LONG render times and overkill typically).

It could also be that your Height just isn't high enough to see the displacement.

Beyond that we'd need to see some images of what you're getting and what your material settings are to help further.

-Brodie

[Bubbaloo]

16 bit tiffs should work just fine as long as the resolution is high enough.

[Bubblegummonster]

Thanks for the replies everyone.

Here is an example

http://imageshack.us/photo/my-images/713/examplequ.jpg/

On the left is zbrush, middle Maya and right maxwell.

You can clearly see that the displacement is working but the edges however still remain look poly like the maya image.

[Bubblegummonster]

Forgot to mention that I'm using a 4096 image map.

[brodie_geers]

That's a tricky one, I've never done character stuff at all. Your map sounds to be plenty good in terms of quality. The only other thing that comes to mind is that within the modeler the smoothing must have a sufficient angle such that Maxwell knows that the corners should be smooth. For example, I believe for a box to have proper displacement in 3ds Max you'd have to set your smoothing angle to over 90 degrees. I've never used Maya but I presume there's a similar function. One thing to try might be to set your smoothing angle very high to see if the displacement works better on those edges.

-Brodie

[Polyxo]

That's a tricky one, I've never done character stuff at all. Your map sounds to be plenty good in terms of quality. The only other thing that comes to mind is that within the modeler the smoothing must have a sufficient angle such that Maxwell knows that the corners should be smooth. For example, I believe for a box to have proper displacement in 3ds Max you'd have to set your smoothing angle to over 90 degrees. I've never used Maya but I presume there's a similar function. One thing to try might be to set your smoothing angle very high to see if the displacement works better on those edges.

-Brodie

What I would suggest you to test is go back to Zbrush, and to simply export a High-Polygon version of the Mesh
and a Normal-Map. Check the Render-Performance now. I would not be surprised if it was a lot faster and of course
without visual defects.
I at least have never experienced any advantage of using Displacement with Maxwell over simply using more Polys + Normal Map
but I don't use Maxwell from a Subdivision-based Host-Program.

If you plan to animate with Maya there's obviously a trick possible with a Plugin which freezes displaced polys before sending to the Renderer.

[Half Life]

The way you make your displacement maps matter in ZBrush, you can end up with very different effects depending on the settings you use -- if you don't mind sharing the ZBrush file I can check it for you.

Best,
Jason.

[Bubblegummonster]

Thanks for the constant support everyone.

Jason, I have no problem sending you the file. I'll post it to you in a bit.

Brodie

I don't think it's the smoothing angle, after all that is just an effect that doesn't change the actual edges. I have noticed that if you don't have any smoothing that the displacement won't work properly and will produce gaps. But I think that's the only reason why in the manual it says to have the smoothing on.

Polyxo.

I also thought of doing this technique. unfortunately when animating if you have too much of a dense mesh it really screw with the weighting and you end up with weird creases as the poly mesh is so dense.


Thanks for the ideas, really appreciate them

[itsallgoode9]

If I remember correctly from a previous thread about this same issue, you basically need to subdivide your mesh much more. like instead 6000 polys, do 60.000 or 600,000. I don't have a link to the thread, as it was from a year ago or so, but somebody trying to do microsuede fabric ran into this same issue. When it comes to displacement and maxwell, the displacement happens perpendicular to the poly plane (which would also the the same as parallel to the poly normal). I don't think the displacement in maxwell takes smoothing normals into account.

I'm not 100% sure this is the case, but i feel like this is what happened in that similar issue. Give it a test and I think it will fix your problem.

[Bubblegummonster]

Hi Itsallgood.


If that's the case then it makes Maxwell a little impractical for character animation, which is a real shame as I love using Maxwell. Ive found that dividing a mesh too high can really start to cause issues with weighting within Maya and you end up with strange abrupt blends that cause creases.

[Bubblegummonster]

Also I've just remembered why I couldn't use a 32bit displacement. When I try to load a tif into maxwell I get an error saying it failed. This only happens with the 32bit tifs, it's fine with 16bit.

Any ideas on this?

[Half Life]

I've looked at it and it is has the double whammy of being too low-poly combined with topology issues (the nose/nostrils have no topology to speak of)... I can get it to work pretty good from subdivision level 3 but the nostrils are still an issue.

Best,
Jason.

[Bubblegummonster]

Hi Jason,

thanks for taking a look. Yes I forgot to say that I wasn't exporting it at level 1, I was exporting it at level 3. Level 3 should have enough detail to allow displacements to work.
I think I'm just going to have to go with Mental ray for this, which is a shame as I love the simplicity of Maxwell.


Thanks for your help, I really appreciate it.

[Polyxo]

@ Jason - just curious:
As you also use Maxwell from a Program which neither outputs Displacement-friendly meshes natively nor gives you access to Subdivision on imported Geo before Rendering:
How do you judge Render-Speed on Low-Poly with Displacement vs relatively HiPoly with a Normal Map (just talking about Still Images here)?