Bumps etc

For all the users of Twilight Render (V1 & V2), to ask questions and get started
olishea
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

Bumps etc

Post by olishea » Mon Sep 28, 2009 3:28 pm

Hi people,

Say I have a texture that I want to bump.

I want to project that texture over a curved surface and use a concrete bump map. (see image, ignore the shapes, its just a test)

How do I keep the texture projected....but keep the bumpmap non-projected ie normal and unstretched.

Sometimes you want a bumpmap that looks completely different to the diffuse map.....but every time I apply bumpmap to a projected texture....the bumpmap is projected too. :cry:

When I try and position the bumpmap....the texture changes to the bumpmap and the render comes out wrong!!

I have looked at the manual and watched the video tutorials but they don't seem to cover this in-depth.

Projected texture over cuboid

Image

Chained bumpmap.....it appears stretched the same as the diffuse map....so I reposition it so it is not projected

Image

Resultant render...diffuse map gone, bumpmap rendered

Image

This occured to me when I was trying to render some candy (boofredlays thread). I projected a stripey texture over the sweet and then tried adding a (concrete) bumpmap....but the bumpmap stretched the same as the original projected texture (see image, I have highlighted stretched bump on verticals)

Image

What am I doing wrong?
Oli

Fletch
Posts: 12906
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
Contact:

Re: Bumps etc

Post by Fletch » Mon Sep 28, 2009 3:58 pm

If you want quite advanced material things like UV map of bump completely unrelated to UV map of diffuse texture:

Export a piece of geometry via .xml
open in Kerkythea
edit texture>save to library
point TWL to see library folder
open SU and scene, use library to apply texture in any scene

olishea
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

Re: Bumps etc

Post by olishea » Mon Sep 28, 2009 4:25 pm

OK I get you.

Thanks for the quick reply, very much appreciated. :)
Oli

Fletch
Posts: 12906
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
Contact:

Re: Bumps etc

Post by Fletch » Mon Sep 28, 2009 5:23 pm

in the case you are talking about though, it may be very difficult to accomplish different UV mapping for bump channel and diffuse (color) channel. Only way I know is to use a procedural texture for the bump channel, as they have 'scale' that can be adjusted, but are independent of the UV mapping.

olishea
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

Re: Bumps etc

Post by olishea » Mon Sep 28, 2009 5:29 pm

I gave up! I would never need this anyway (except for translucent, stripey, bumpy candy!!!) haha

Cheers anyway mate, at least I understand all the chains now! :lol:
Oli

Ecuadorian
Posts: 1779
Joined: Fri Mar 20, 2009 3:43 pm
OS: Windows 7 Pro 64-bit
SketchUp: 7.1
Location: Guayaquil, Ecuador
Contact:

Re: Bumps etc

Post by Ecuadorian » Mon Sep 28, 2009 5:38 pm

Chained = same as SketchUp material, with two-way communication.

Oli, you could right click > Make Unique Texture and use the newly created material for those odd surfaces.

Fletch
Posts: 12906
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
Contact:

Re: Bumps etc

Post by Fletch » Mon Sep 28, 2009 5:46 pm

Ecuadorian wrote:use the newly created material for those odd surfaces.
this would work! and wouldn't involve leaving KT... I often forget about that 'make unique texture' function. ;)
remember when loading a special texture for your bump to break the link first before loading the texture.

olishea
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

Re: Bumps etc

Post by olishea » Mon Sep 28, 2009 7:19 pm

Yes I tried this.....but didn't break the link, thats where I went wrong. NICE ONE GUYS!!! :D
Oli

Chris
Posts: 5346
Joined: Sun Mar 08, 2009 3:00 am
OS: Win10
SketchUp: 2016

Re: Bumps etc

Post by Chris » Mon Sep 28, 2009 8:34 pm

You can specify different textures for bump map and diffuse, but you can never specify different UV coordinates. SU simply only supports one set of UV coordinates. As Fletch suggested, you can add different offset, scale, and rotation via a library material, but for those are simple modifications of the existing UV coordinates. For something as complicated as projected for diffuse and non-projected for bump, that's just not possible.

Fletch
Posts: 12906
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2023
Contact:

Re: Bumps etc

Post by Fletch » Tue Sep 29, 2009 7:31 am

This is something that would be extremely difficult if not impossible to do if not for the "make unique texture" function in SketchUp. It turns something deep and advanced into something quite simple... I love that.

After using SketchUp's context-click "Make Unique Texture" you will need to apply a material template to the new texture and be sure the bump link is broken, then apply the bump map to it.

Post Reply

Who is online

Users browsing this forum: No registered users and 10 guests