Using maps without SU UV mapping

[thomthom]

As you probably know, when you only have a colour instead of a texture in the diffuse channel, SU won't generate UV mapping.

So for instance, when you wanted an opacity map for a material with a plain colour, a work around often involves adding the opacity map to the default diffuse layer and set it's opacity to 0 so it's invisible, and then create a second diffuse layer which is visible.

What I just notices is that if you don't have any UV mapping, a map with UV tiling 1.0, 1.0 means the map will be 1 inch by 1 inch.

So you can calculate how large it needs to be. For instance, to make a map be 1000x1000x, you set the UV tiling to 0.0254, 0.0254.

Simply divide 25.4 by the length you want. (if you're using mm)

If you want a map to be 2400x1200mm:
U: 25.4 / 2400 = 0,010583
V: 25.4 / 1200 = 0,021166

This works fine for flat surfaces. Not sure how predictable it is if you got curved surface.

Example where a checker map is sized to fit 1000x1000mm:

[OzBoz]

Re: Using maps without SU UV mapping

Very useful!! There is not much about mapping in the manual. And glad you found a link between real world measurements and the rest. Think at the webinar I saw also a trick by just making the diffuse layer transparant. So it does have mapping, but you don't see the map you attached to the diffuse layer anymore.

[thomthom]

Re: Using maps without SU UV mapping

Very useful!! There is not much about mapping in the manual. And glad you found a link between real world measurements and the rest. Think at the webinar I saw also a trick by just making the diffuse layer transparant. So it does have mapping, but you don't see the map you attached to the diffuse layer anymore.

Yes, I've used that technique myself. But the downside is that it makes the objects transparent, which isn't good if the model doubles as a SU presentation model.

[Jackson_cg]

Re: Using maps without SU UV mapping

As you probably know, when you only have a colour instead of a texture in the diffuse channel, SU won't generate UV mapping.

So for instance, when you wanted an opacity map for a material with a plain colour, a work around often involves adding the opacity map to the default diffuse layer and set it's opacity to 0 so it's invisible, and then create a second diffuse layer which is visible.

Another workaround is to put any square bitmap (I use a 255 white jpg) in SU's material diffuse slot and set the colour in SU. Then in the VfSU Material Editor change the diffuse Blend Ratio to 1 so the diffuse bitmap is completely overridden by the SU colour choice. This way only the colour will render, but VfSU still has UV coordinates from the now-invisible bitmap so you can adjust bump maps , clip maps, etc as you wish without having to add an extra diffuse layer. Using SU's texture position editor you can even manually alter the UV mapping for each individual face.

[nomeradona_cg]

Re: Using maps without SU UV mapping

As you probably know, when you only have a colour instead of a texture in the diffuse channel, SU won't generate UV mapping.

So for instance, when you wanted an opacity map for a material with a plain colour, a work around often involves adding the opacity map to the default diffuse layer and set it's opacity to 0 so it's invisible, and then create a second diffuse layer which is visible.

What I just notices is that if you don't have any UV mapping, a map with UV tiling 1.0, 1.0 means the map will be 1 inch by 1 inch.

So you can calculate how large it needs to be. For instance, to make a map be 1000x1000x, you set the UV tiling to 0.0254, 0.0254.

Simply divide 25.4 by the length you want. (if you're using mm)

If you want a map to be 2400x1200mm:
U: 25.4 / 2400 = 0,010583
V: 25.4 / 1200 = 0,021166

This works fine for flat surfaces. Not sure how predictable it is if you got curved surface.

Example where a checker map is sized to fit 1000x1000mm:

thanks for this observation

[thomthom]

Re: Using maps without SU UV mapping

As you probably know, when you only have a colour instead of a texture in the diffuse channel, SU won't generate UV mapping.

So for instance, when you wanted an opacity map for a material with a plain colour, a work around often involves adding the opacity map to the default diffuse layer and set it's opacity to 0 so it's invisible, and then create a second diffuse layer which is visible.

Another workaround is to put any square bitmap (I use a 255 white jpg) in SU's material diffuse slot and set the colour in SU. Then in the VfSU Material Editor change the diffuse Blend Ratio to 1 so the diffuse bitmap is completely overridden by the SU colour choice. This way only the colour will render, but VfSU still has UV coordinates from the now-invisible bitmap so you can adjust bump maps , clip maps, etc as you wish without having to add an extra diffuse layer. Using SU's texture position editor you can even manually alter the UV mapping for each individual face.

Ah yea, the Blend material. That's an option too.

[40th]

Re: Using maps without SU UV mapping

Thanks for the tips guys.

[Hanswurst_cg]

Re: Using maps without SU UV mapping

Does vray for SU alway consider a texture-map to be square? Or are there any limitation in Teture-sizes? I had some problems recently with a material that used a rectangular Texture of 1000mm by 300mm (HxB PNG Bitmap).

The diffuse texture alway seemed to be disorted (streched in width) in Sketchup after appling the material to the surface.

I am able to compensate the disortion in the v u setting of the texture, but this "workaround" didn't show up in the sketchup-model, so a correct aligning the texture on the sketchup-Model was almost impossible.

[Jackson_cg]

Re: Using maps without SU UV mapping

You can adjust the proportions of any shaped texture bitmap in SU's Material Editor. It's slow to respond, but click on the "chain link" icon to toggle contrain/unconstrain proportions and then adjust the x and y scale of your texture by typing in the appropriate numbers into the dimension fields (e.g. 1000mm x 300mm would give the correct proportions for your example). V-Ray reads the UV mapping from SU automatically.

[thomthom]

Re: Using maps without SU UV mapping

Does vray for SU alway consider a texture-map to be square? Or are there any limitation in Teture-sizes? I had some problems recently with a material that used a rectangular Texture of 1000mm by 300mm (HxB PNG Bitmap).

The diffuse texture alway seemed to be disorted (streched in width) in Sketchup after appling the material to the surface.

I am able to compensate the disortion in the v u setting of the texture, but this "workaround" didn't show up in the sketchup-model, so a correct aligning the texture on the sketchup-Model was almost impossible.

Did you create the material using V-Rays material editor or SU's?
I always use SU to create the base of the materials and have never had problems with non-square textures.

[Hanswurst_cg]

Re: Using maps without SU UV mapping

In the case of this specific matrial I duplicatet an existing glas material (architectual glass) to make an "facade"-matrial of it including the neccesary framework for the glassplanes.

I applied several changes to the glass mat.:
1. applied the bitmap to the fresnel-channels to make only the glassplanes reflective
2. applied a second diffuse on top of the transparend "glass" diffuse (this layer shoud be the framework)
3. applied a transparancy-map to teh second diffuse (to make the framework opaque and keep the glasspalnes transparent)
4. applied a texture in the second diffuse-channel to align the texture in skp. (what in my case didn't work out correctly)

so this is the way I created the material.

I'll try the adjusting- tip that Jackson gave me and call back afterwards.

maybe I'll find a place where I can upload a pic or the vismat to show better.... but for now Thanks a Lot guy's ;D

[Hanswurst_cg]

Re: Using maps without SU UV mapping

YOHOOOOO It WOrked!

thath skp adjusting did the trick - now i can align the facade correctly to my model and do'nt need to model each window for it's own

here is a lilltle picture of the material used... nothing special just a test render...

and again... THANK YOU!

[AcesHigh]

Re: Using maps without SU UV mapping

What I just notices is that if you don't have any UV mapping, a map with UV tiling 1.0, 1.0 means the map will be 1 inch by 1 inch.

am I the only one who thinks its very annoying that VRAY default units are INCHES?? Why not metric?

[thomthom]

Re: Using maps without SU UV mapping

What I just notices is that if you don't have any UV mapping, a map with UV tiling 1.0, 1.0 means the map will be 1 inch by 1 inch.

am I the only one who thinks its very annoying that VRAY default units are INCHES?? Why not metric?

It is not V-Ray default units - it's Sketchup's default units. Internally everything is in inches - though ASGVis has not been aware of that it seems. And yes, it's annoying. I've been going on about it in the beta forum.