UV Mapping confusion

[ROI]

UV Mapping confusion

Hi Martin,

I'm trying to apply a stone texture to an object, like this:
1) I made a new Material, and gave it a texture (a jpg of some stone blocks).
2) I made a box object, made it editable, and applied the material as a tag.
3) I clicked on the UV Mapping tool...

Now I can see 3 different ways to change the way the stone appears on the object:
a) by changing the 'Properties' of the box's material tag (UV offset, UV rotation and UV scale)
b) by changing the 'Transformation' values in the UV Mapper tool (offset and scale, but no rotation)
c) by dragging/stretching/rotating the orange frame.

My question is, how are these 3 related? I would expect (b) and (c) to cause (a) to change when I click 'write UV coords', but this doesn't happen. Once the coords are written to the object I don't see any way of tweaking them (since the orange box gets reset when I press escape). Surely the object should have just one set of parameters to describe how the texture is displayed?

Thanks for your help.

(v3.2 looks great, by the way)

 

[Martin]

Hi,
lets start with

c) Use this to modify the mapping geomerty.

b) In case of spherical mapping you can't change the scale of the texture just by scaling the mapping geometry. So you have to use the "offset" and "scale" properties of b) to perform that.

a) last but not least you can modify uvcoords with the properties of the material tag. This last transform of the UV coords is performed before the geometry is sent to OpenGL or the raytracer. With this properties you can even affect the uv coords of parametric objects.


So if you assign UV coords to a polygon object first c) will be preformed then b) and at last a).

As you can see a), b) and c) all have a practical usage.

I hope that helps.

Regards,
Martin

 

[Randolph]

This is only tangentially related, but I wish that there was a way to scale the bitmap images within the material properties, i.e. globally. When using a texture map of wood grain, I end up having to go through each piece of geometry and ajust the scale and rotation to have all the graing going the direction it should on a piece of furniture. Would it be difficult to add this feature at the global level?

randolph

 

[Martin]

Would it be difficult to add this feature at the global level?

It isn't difficult but I think it would mess up the UI a little bit if there are to many properties in the shaders. Especially properties which don't everybody need.

Bye,
Martin