Multipass-Rendering / Layers, Channels for Post Production

[nicolas_willms]

Hi there,
we're a small Architecture Office, rendering only from time to time. Last time we used Cinema 4d (R20) + VRay (v3.7) was some time ago... Now we've updated to the latest Version of Vray for C4D (v6) on Mac OS Ventura and found lots of improvements (loving the Cosmos Browser), but also lost track of the possibility to render to a layer-based PSD- / Photoshop file.

After rendering we usually improve the images in Photoshop. For that we assigned channels to materials and objects (Material-ID / Object-ID) and saved the Rendering to a layer-based PSD- / Photoshop file to work with the selections and Alpha-Channel.

What I've learned so far is that I have to use VRay Render Elements. There I also found several Elements, like 'Material ID', Object ID' and so on. I also assigned a VRayObjectProperties VRay-Tag, in which I defined a certain Object ID. In the Material Manager I enabled Material ID, Multimatte ID (also in Render Elements).

On to the Render Settings - all I found was Multipass (with Object Channels), so I enabled this option.

Now - when Rendering in the Picture Manager, the object channels remain black. In the PSD-file there are no channels for Object-ID / Material-ID either. The only thing that comes to life is the Alpha-Channel.

What am I doing wrong? As always, we' re kind of in a hurry...


Thanks in advance,
Nicolas

[sirio76]

Hi Nicolas,
You can get all the mask that you need, but I strongly suggest to do most of the post production inside the VFB, today is much more practical and fast, and you can perform most of the PS corrections.
There is a render element called cryptomatte, by using it you will be able to create instantly all the mask (I use two, one in render ID and one in material mode).
If needed you can also tune individual lights using the lightmix and in composite mode you can perform more advanced stuff.
Here is a video in 3 part that I’ve made some time ago for Chaos and D2, it covers all the workflow from CAD to final render, post production is in part 3, from minute 21:

https://www.youtube.com/watch?v=_UFt0-qzMUI

If you still want to use masks in PS I can show how to do that, but I strongly recommend to adapt to a new workflow and use the VFB, today I barely use PS, maybe just for the very final touch.

[nicolas_willms]

Hello Sirio,
thank you for your time and effort! You have an interesting Youtube Channel, I'll check it out for sure. You may be right, VFB may be the better way. I previously checked it out - even though found the Material ID / Object ID there, I still couldn't extract a Layer-based File with the wanted channels (Alpha-Channel did work, though).

Since time for the actual Renderings is running out, I would be really happy, if you could show me how to render the old way to a psd-file with the selected Material- and Object-Channels. But, since there are an increasing number of renderings ahead, I'll make sure to study your videos and learn a maybe better workflow afterwards

Regards, Nicolas

[aleksandar.kasabov]

Hello nicolas_willms,

If you want to render with the Picture Viewer and save a PSD file with all render elements, simply enable the Multi-Pass and add Post effects in the render settings. Then set your Multi-Pass output in the Save system as shown here. After the render is completed, you will have the layered PSD file, saved in your directory. I hope this is of help.

[nicolas_willms]

Hello Aleksandar,

thanks a lot, that did the job!

Now at least I get a PSD file with layers. Still some questions remain:

- Since I get a multi-layered PSD-file - is there a chance to render the selection into Psd channels (like the Alpha channel), not PSD Layers? This would save some steps in the selecting process.
- When selecting 'Object Select' in the VRay Render Elements, in the output there are three layers for each Object ('Object Select', 'Object Select_filter' and 'Object Select_alpha'). Is this necessary / how to reduce this to a single Layer / Channel?
- In my project, there are several physical materials. Where do I add the Material ID and what's the best way to select them in the Render Elements?

Sorry for asking so much!

[aleksandar.kasabov]

Hello nicolas_willms,

- Since I get a multi-layered PSD-file - is there a chance to render the selection into Psd channels (like the Alpha channel), not PSD Layers? This would save some steps in the selecting process.

The method, described above uses the native Cinema4D save system and the way it works is by adding the render elements to separate layers. This is needed when you are compositing multiple render elements.

- When selecting 'Object Select' in the VRay Render Elements, in the output there are three layers for each Object ('Object Select', 'Object Select_filter' and 'Object Select_alpha'). Is this necessary / how to reduce this to a single Layer / Channel?

Currently, this render element will generate all 3 layers. We have a request to add an option to choose which layers to be generated from Object select RE (request ID: VC4D-1802). I will let you know once we have any updates. This topic has also been discussed here.

- In my project, there are several physical materials. Where do I add the Material ID and what's the best way to select them in the Render Elements?

Can you please elaborate on what materials you have in your scene? Are you referring to native Cinema4D materials? If that is the case, please note that V-Ray render elements will only work with V-Ray materials. You can consider converting your materials to V-Ray node materials using our material converter. More about it can be found here.

[nicolas_willms]

Hello Aleksandar,

thank you for your answers.

- In older versions (correct me if I'm wrong) I think there was a possibility (in Cinema 4D, not VRay) to save the selections directly into PSD-Channels, not Layers. But I lost track of that option some C4D-Versions ago. Maybe C4D R20 doesn't support this option anymore. I understand that this might not be a problem not connected to VRay though, maybe someone knows nevertheless

- I'll be looking forward to the option to choose between the three layers.

- The material converter did the job for me, thank you!