Maya and displacement maps for hi-poly detail

BobbysWineGums

Hi,

I have an issue with using displacement maps for creating high polycount meshes for export to an external renderer. (Maya/Arnold)

The problem is that I'm having to create so many iteration levels to try to eliminate what looks like low-res jaggies on the edge of my resulting models/renders, that the baked object meshes are getting MASSIVE.

If it's the source image for displacement map that's the issue, can someone tell me the optimum filetype of method for creating them? I use Adobe Illustrator and Photoshop mainly for creating png files but have tried .tiff files also, generally white on black images...should I be using alpha channels instead? I'm just trying to get straight lines, the source image is straight but on applying it to the mesh the 'wall' tend to develop wavy lines or ridges...I must be doing something wrong surely?

I'm putting embosses on objects, I even learnt ZBrush but then had all sort of problems exporting models to renderer so gave up on that for the moment.

Help me Obiwan, you're my only hope!!

Dan

oglu

Show us some images.
If you like to use the data in zbrush just displace the object there.

sprunghunt

I found for pre-rendered images that it's usually just as efficient to use a very high poly object instead of displacement mapping. Displacement maps take up just as much memory and render a little slower because the tesselation needs to be calculated. 

However it sounds like your problem is that the displacement maps are too small a bit depth. You want a 32 bit depth image. This can be just a regular PSD file. 

Have you read the documentation? there's lots of setup tips in there:
https://docs.arnoldrenderer.com/display/A5AFMUG/Displacement

BobbysWineGums

Here's a closeup of the one displaced 'lattice' shape, it's a box with this lattice shape all over it and the model is at 5 iterations on a fairly well sub-divided box mesh already and the .obj file is about 500Mb, I'm guessing it's the triangle tasselations that stretch out at the edge of the white on black image. This result is from a 300dpi png file at 22175px x 22175px.

Ah, right, didn't know it could take in psd, I'll give that a go and read that article too, thanks!

Dan

BobbysWineGums

PSD file doesn't help, using a gaussian blur does though (the image above has a slight blur, the one i just did from a psd file didn't and the triangles visible were far more defined). Is it anything to do with how the tx file is created, are there any options for controlling that? Also, I use black and white images, are transparent/alpha images better at all?

sprunghunt

BobbysWineGums said:

Here's a closeup of the one displaced 'lattice' shape, it's a box with this lattice shape all over it and the model is at 5 iterations on a fairly well sub-divided box mesh already and the .obj file is about 500Mb, I'm guessing it's the triangle tasselations that stretch out at the edge of the white on black image. This result is from a 300dpi png file at 22175px x 22175px.

Ah, right, didn't know it could take in psd, I'll give that a go and read that article too, thanks!

Dan

Doing a hard surface model with displacement is a bad idea. Displacement is good for rough surfaces like tree trunks or skin. It's not good for armor or machines because you're going to be trying to draw diagonal lines across a grid. 

As I said before it would be simpler to just have a very high poly model. 

BobbysWineGums

Thanks again, I’ve not done that other than playing with ZBrush or Mudbox, is that what you would use?