Changing Texture Colour Using Specific RGB

[anita_brown]

Hey guys, fairly new user of V-Ray here, having come from using Maxwell Render for 9 years. I've been using the monthly subscription to test V-Ray before I decide to use it full time (in my online courses) and I'm experiencing a few teething problems. To be honest, for the reputation and endorsements that V-Ray has internationally I was expecting the relationship between V-Ray and SketchUp materials to be better. I'm slightly disappointed that changes I make to SketchUp materials, where there is a texture aren't copied to the V-Ray interface (unless I'm wrong here). Even changes I make to materials in the V-Ray interface aren't updated in the SketchUp scene, which I consider a basic function. Unless, I'm wrong about this and if I am, I'd love someone to clarify this, or send me to the relevant tutorials for more information.

My workflow in all the other rendering applications I've used to date is to apply textures via SketchUp, make any modifications to colour/tone etc. using SketchUp's materials editor and then do a test render to see how the textures appear initially. This is a pretty seamless process but in V-Ray is has become much less efficient because changes to the RGB of textures aren't carried over into the V-Ray interface. The most logical thing to do here is to take a note of the RGB of the texture colour in SketchUp and then input these in the V-Ray interface for the same material but all I can see is a sliding 'hue' scale and adjustments to brightness/contrast/saturation which isn't giving me enough control.

I also use the 'match colour' function in SketchUp a lot, and this is also a workflow that is suffering somewhat due to the lack of interaction between the two interfaces.

I would really appreciate if someone could clarify if my current understanding of the above is correct and how I change the RGB levels of textures in V-Ray, or refer me to the relevant resources.

Thanks,
Anita

[konstantin_chaos]

Hi anita_brown,

There are a couple of things to consider when working with V-Ray in SketchUp:

Every SketchUp material you create has a V-Ray counterpart that can be managed within the Asset Editor.
The opposite of this applies also - V-Ray materials get listed in SketchUp.
When there is no texture used the color of the SU material is connected to the V-Ray one and changing one will update the other automatically.

There are some specifics when you apply a texture though.
When a texture is added a similar connection is established and the two interfaces are synchronized.
Keep in mind though that SketchUp loads the texture and stores it in the skp file while V-Ray references the texture on disk.
This allows V-Ray to use more than one texture per material without making the model bigger in size.
It also means that you'll have to manage external file textures if you intend to move the project to another location or another computer.

When using the color correction feature of SketchUp you should see the result rendered in V-Ray by default.
The correction will however not show in the V-Ray's asset editor.
The reason for this is we're applying the correction during render time and the editor doesn't know about it.
This is something we can potentially try to improve in the future (even though it will not be a trivial task).

There are 2 potential workflows you can use to keep things simple:

1. Use SketchUp's material editor for simple materials and ignore the fact that the colorization doesn't appear in the V-Ray's asset editor.
2. Use only the V-Ray material editing capabilities. This way you'll be able to take advantage of all the powerful material editing features that V-Ray offers.
   To color correct textures in the Asset Editor you can just add one of the correction maps between your material and the texture.

Hope that clarifies things to some extent,
Konstantin

[anita_brown]

Hi konstantin_chaos

Thank you for your prompt reply and for taking me through those points. I clearly need to go back and familiarise myself with the interface again. Although, if I opt to use the V-Ray material editing capabilities only, how do I change texture colours using RGB?

By the way, I've been undertaking a lot of render tests on V-Ray this weekend and I've been using CPU, GPU and Hybrid rendering and I'm VERY impressed!

I was wondering if you could help me with a query regarding my current set-up and if the new spec I'm going to get is the right decision? I'll be recommending this to my students too, so it's important that I get it right.

Thanks,
Anita