Nuke operators on textuers - dos and don'ts?

[frueter]

Hi,

so I have been trying to always pre-render my comp branches and convert them to tiled exrs, then reading the latter into a VRayTexBitmap node before using it as a texture for VRay.
I am wondering though if it's detrimental to render times to use, say, a simple Transform node between the VRayTexBitmap node and the material, or simple Grade node?
In a nutshell, is there any information that will help judge when it's fine to do a quick "live" adjustment on a texture with standard Nuke nodes and when one should start pre-rendering again?

Any tips would be great to know on this level or is it as simple as "never, ever use anything but a VRayTexBitmap node as a texture input"?

Cheers,
frank

[georgi.zhekov]

Hey,

Nuke operators are totally okey to be used - the only time you will need to pre-render is when you want to use V-Ray Standalone.

While rendering inside of Nuke they should be working correctly.

[frueter]

Thanks. What about speed issues? I remember having a few nodes upstream of a texture input could slow down the renders drastically. Is that still the case?

[georgi.zhekov]

Depends on the operations - baked textures will always be faster as there won't be any additional calculations.

If there is anything extremely slow - send it to us and we'll see what we can do

[Christophe.Cot]

Frank,
Obviously any image modifier will induce additional calculation along the DAG which in theory could impact render time.
It depends on many factors, on the number of modifiers etc... so it's hard to define but I guess that most usual image modifiers are pretty fast.
If you connect a viewer directly to the texture branch output and you notice it takes some time to get the output, then baking might be beneficial.
On top of that Nuke tends to minimize recalculation by caching a lot of data. If you have a texture branch with various modifiers, it should cache the output of this and reuse it when possible if nothing change on the affected nodes.

You might also want to look at the so called performance metrics command line argument when launching Nuke (check out the command line help for more info).
This is supposingly giving some useful data of resource spent on each nodes and should highlight nodes where most of the calculation happens.

Chris

[frueter]

Thanks guys. I just seem to recall that a year or two ago the dogma was to always render out upstream branches and ideally convert them to tiled exrs instead of hooking up Nuke nodes.
I still like to do this to stay compatible with standalone rendering but was wondering if an extra Grade or Transform node between the VRayTexBitmap and the geo would still introduce undue slowness. Sounds like this is ok to do though.
Cheers,
frank