Arnold Q&A

[sant0s]

hehe, sry
no - I understand for what the sta_vector_displ stands, but you said, that this shader also works for "normal" displacement and the "old" one is for old scenes.
so the sta_vector_displacement should work for normal displacement without the "old" shader.
Actually what I wonder only, if the way I connect the vector_state is correct or just some bad workaround. And if i do not need it, how can I avoid that the displacement is lean?
And, slap me if I am wrong, I cannot find any info on the old displacement shader, even not as a user_property
sry for beeing that n00bish, guess its a simple logical mind mistake

[Rork]

You're misreading my posts...
Forget about the sta_displacement node, it's only there for compatibility on old SitoA scenes. There's no PPG.
Workflow changed into what we have now with the property. Sorry if that confused you.

Use the property on the model, and dial in "Subdivision Iterations" and "Autobump" on or off, for you standard displacements.

When you sculpted something in ZBrush or Mudbox, export a vector file, and than use the sta_vector_displacement.
That's all there is to it.

[Dwindleflip]

Here's an image showing the displacement problems. Whats the best option to map displacement for something like this.

So far it seems its best to set subdivision type to linear, and just live with the stretching. There seems no way to map a subdiv wall tho without uv smoothing ruining everything. And there seems to be no micro poly displacement or mental ray fine displacement for just regular polygon objects (non subdiv)

[Rork]

You're running into a know issue when normals 'pass a corner'. This is from the SitoA mailinglist:

Q: is there any way to have the rendertime additional subdivisions on an object respect (hard) edges? Is there any way to have the rendertime additional subdivisions on an object respect hard edges?

A: your polygon mesh primitive has an attribute called 'subdivion rule'. Set that to Linear. Or create a User Option property with 'subdiv_type linear' as option.
This will keep the overall shape of the pieces but subdivide them, so you'll have more polys to displace.

Note on the topic: The "linear" subdiv type is rarely needed, and it comes with its own set of issues. Notice how the edges of the displaced cube look smoother than the inside of the faces. That's because it's not clear for the renderer which normal vector to use in the edges out of the two adjacent sides -- it's an ill-defined problem. If i remember correctly, Arnold chooses whatever vertex appeared first in the mesh, an arbitrary choice. This may or may not be a problem for your particular scene, but it could be for others.

Hope this helps,

Rob

[Dwindleflip]

Thanks that confirms my findings. Linear division seems to be the only imperfect solution for these situations. Is there any way to get a good result out of arnold for this kind of situation?

Mental Ray's fine displacement seems to do a better job with this

[sant0s]

how to work with the realativ and absolut path system?

For example, I have a scene with standins located in Render_Archive.

Now I export that complete scene again, do I have to check or uncheck the Absolut Path in the Arnold settings?

Actually I would like to send one big .ass file and a seperate cam to another computer - but what every I try, there is always pointing something to a wrong path.

Could anybody give me a workflow or little scene where an .ass is inside an .ass and at least on image is in pictures?

thx!

edit: did a workaround I guess - just always untick the "absolut path" field under the ass tab and use the export selected funktion, not the export under the ass tab.