How Vray renders a material that had its colour changed on Sketchup

[Beardyfella]

Hey folks!

I've been a VfSU user for quite some time now. I'm doing my Architecture major and i gotta say it changed my world.

I'm having this small problem since i migrated from SR1 to SR1.5, though.

Everytime i try to change the colour of a material on SketchUp and then render on V-ray, i get no change at all. I see the new V-ray automatically creates a material for every SU material applied to the model, and i've noticed the ones i changed the colour are Blend instead of simple Bitmaps.

I've added some images to better explain my issue:
With V-ray 1.5 -

With V-ray 1.0 (this also looks weird, by the way.... i'm sure i created a new material for the dark stone but it's being displayed as the same material... maybe it has something to do with the fact that i created the file on V-ray 1.5 and then rendered on 1.0) -

With SketchUp -



Does anyone know what i'm doing wrong? How can i get that old functionality back?

I'm currently using SU6 and Vray 1.5.30.

Thanks in advance!

[thomthom]

Re: How Vray renders a material that had its colour changed on Sketchup

I've found that using SU to adjust colour tones in textures isn't very reliable. I do the adjustments in Photoshop.

[Jackson_cg]

Re: How Vray renders a material that had its colour changed on Sketchup

Ditto.

IMO the VfSU "blend" method of interpreting SU's H,L,S adjusted materials is more or less useless. Whereas SU will display a pretty decent HLS adjusted version of the original diffuse map (most of the time) VRay just creates this dumb 50/50 mix which results in a washed-out diffuse map and often very weird colouring. An extreme example is when you create a material in SU from an coloured bitmap, but reduce the saturation to zero. VfSU will convert this to a blend of the coloured bitmap and a grey diffuse colour- nothing like the desaturated SU material.

I know that just the way VRay works and so the "blend" method is ASGvis's way of getting VRay's Material Editor to cooperate with SU's Material Editor, but shortly after getting into VRay I completely stopped using SU adjusted texures. Like Thomthom says, it's better to get in the habit of adjusting your diffuse bitmaps in Photoshop and then you'll avoid the whole What-You-See-Is-Not-What-You-Get blended material problem. It'll also give you much more control over how your materials actually render as you'll be able to customise them to a much higher degree than simply via the SU Material Editor.

Of course VRay blended maps can be extremely useful for all sorts of other things- bump, tranparency, environment, GI etc, but I avoid them for ordinary materials.

[Beardyfella]

Re: How Vray renders a material that had its colour changed on Sketchup

Oh... well... What really bothers me is that it was a pretty quick way to achieve a fairly decent result. Also, it was working with SR1 and completely stopped working on SR1.5.

Hopefully, it will be fixed for the next release.

Thanks for the replies, guys!

[dalomar_cg]

Re: How Vray renders a material that had its colour changed on Sketchup

First of all agree very much with Jackson and Thomas...there's really no parallel for this kind of adjustment in other rendering softwares, so its a very odd thing to support. This kind of thing is definitely something that would be more accurately and reliably done in photoshop.

Secondly, It may just be me, but you're example is slightly confusing to me. Your Sketchup screenshot shows two different materials on the cubes, yet in both of the V-Ray renderings neither one is correct. So A) how do you have the materials applied in SketchUp? B) Are their two materials or just one? C) are there any special things about the geometry you're applying the material to (are they components/groups...is the material applied on the geometry or on the group/component) D) Is the blend map actually created and if it is, does any colorization get echoed into the V-Ray interface?

I will say that colorizing the material in SU is something that has worked for me, but it has been one of the flakier parts of the material connection to SU. I've seen issues, but have not been able to track them down exactly.

[kwistenbiebel1]

Re: How Vray renders a material that had its colour changed on Sketchup

Vrayfor Su should have its own texture editor (just like Maxwell, fry etc...) with contrast, brightness, black/white clip , saturation etc....
It is very strange that it isn't a built in feature as the sketchup texture editor is crap and Vray currently does a bad conversion with the automatic blending option.
Most of the time, the blending basically washes out the textures.

Going back and forth to Photoshop for slight texture changes is a workflow killer.

To me this is a major thing that hopefully will be adressed.
It's one of those things that really shows the difference with Vray versions on other platforms.

[Beardyfella]

Re: How Vray renders a material that had its colour changed on Sketchup

Secondly, It may just be me, but you're example is slightly confusing to me. Your Sketchup screenshot shows two different materials on the cubes, yet in both of the V-Ray renderings neither one is correct

Yes, very much. That was due to the fact that i created the whole file on Sketchup 7 with V-ray 1.5 and then simply opened it on the pervious SU and VR versions. That's what must have caused that problem.

A) how do you have the materials applied in SketchUp?

They are 2 independent materials, one is the original SU material and the other was created based on the first one, but changing the colour of the texture.

B) Are their two materials or just one?

They're two separate materials.

C) are there any special things about the geometry you're applying the material to (are they components/groups...is the material applied on the geometry or on the group/component)

They are groups and the material is applied to the whole groups, not the independent faces.

D) Is the blend map actually created and if it is, does any colorization get echoed into the V-Ray interface?

Yes, it's being created and no, it doesn't seem to have any effect whatsoever on the rendering.

So, i'll do the whole test again:
SketchUp:

VR SR1.0:

VR SR1.5:


Here are two links to the model:
SU6+VR1.0: http://rapidshare.com/files/24937372...st_v6.skp.html
SU7+VR1.5: http://rapidshare.com/files/24937421...st_v7.skp.html


What really bothers me is that is was working with SR 1.0 and stopped with SR 1.5... i guess it has something to do with the automate linkage VR does with SU materials now.

And i know it isn't reliable, but it's somewhat odd that SketchUp offers an option to tweak the colour and saturation of the material and V-ray simply doesn't follow it. The "edit all your textures with Photoshop or another image editing software" should be a recommendation (which i will follow from now on), not the only choice avaliable.

Anyways, i'm hoping for changes on the next release.

Thanks for the feedback, guys!

[thomthom]

Re: How Vray renders a material that had its colour changed on Sketchup

Are they groups? Is one a copy of the other?

There could be a SU group bug in play here.

[dalomar_cg]

Re: How Vray renders a material that had its colour changed on Sketchup

Yea, I think the second group with the color blended texture is a copy of the first uncolorized one. I think this is more of an issue of how groups and material applications on groups are handled within sketchup. Basically, I don't think we're getting told the correct information from SU about the modification that's been made.

I just did a quick test here, and see what you're seeing if I copy the group with the material already applied, then apply a new material (that was created from the old one) that's been colorized on top of the copy, I don't see a change. However, if I either apply the material on the geometry itself or explode, immediately recreate the group, its fine.

[edonk]

Re: How Vray renders a material that had its colour changed on Sketchup

I just did a quick test here, and see what you're seeing if I copy the group with the material already applied, then apply a new material (that was created from the old one) that's been colorized on top of the copy, I don't see a change. However, if I either apply the material on the geometry itself or explode, immediately recreate the group, its fine.

I dont mean to butt in here, but I thought we'd already established in other threads that it is best to apply materials direct to geometry and not groups? Thats the way I understood anyway, and it is now my current workflow.

[Jackson_cg]

Re: How Vray renders a material that had its colour changed on Sketchup

I dont mean to butt in here, but I thought we'd already established in other threads that it is best to apply materials direct to geometry and not groups?

It is ; not doing so is what's causing the bug above. There's no contradiction in Dalomar's post- by exploding and regrouping a group with a material already applied to it, SU automatically applies the material directly to the geometry. Whichever way you do it, as long as the material ends up applied directly to geometry, VfSU should be able to read the SU material information correctly.

Matthieu Noblet's "Remove CG" ruby script does the same thing on a global basis, so you can "texture by group" as you work on the model if you want, as long as you run the script before you start rendering.

[Beardyfella]

Re: How Vray renders a material that had its colour changed on Sketchup

Ok, my bad. I didn't know the group bug had such ramification. Exploding the group and regrouping solved part of the problem.

The issue now is how V-Ray is interpreting the colour change SketchUp applies to a texture. Since i regrouped, i can see some reflect of the texture, but it's far less accurate than what we were getting with SR1. You can see that by comparting the results i showed on the first (and fairly bugged) test.

It seems to me that SR1 imported the already changed texture instead of applying a blend colour to it... it had a better result, in my humble opinion.

[dalomar_cg]

Re: How Vray renders a material that had its colour changed on Sketchup

I think what might be a better operation is to multiply the image by the color your trying to tint it with. This should lead to a "less dull" result. However, I don't believe that will give the results exactly like you see in SU. I think SU might be doing the equivalent of Photoshop's Overlay blend mode which is a combination of multiplication and addition.

We stepped away from loading the colorized version because it cause issues with temporary file issues and keeping track of image changes and things, so I don't think we'd like to go back to that. So if anyone knows exactly how SU is colorizing the texture (I'm sure its not that complicated) than that would helpful in us getting you the results you're looking for.

[thomthom]

Re: How Vray renders a material that had its colour changed on Sketchup

I believe it works more like PS's Hue/Saturation adjustment method.

you have the option to adjust the HSL values, which basically just shifts the values in HSL space or you can colorize it, turns the image into a grayscale and then tint the grayscale image with the given colour.

[giorgione]

Re: How Vray renders a material that had its colour changed on Sketchup

I found very usefull to assign different material to various (same) components.
Immagine lot of equal boxes with different colors.
If I have many equal components and I apply different materials Vray renders all the component with the material pplied to the first created component.
Is there a way to solve this problem?
Or do I have to creat all different component for each color?