Why resampling of texture image when it is multiple used?



I have a photo of a panel, which I have used as texture at many places in my model. Since the photo is not straight I have adjusted the texture position for each use, to fit the model. But oups! My exported Collada file exploded in size. Now it contains several copies of the original image, just slightly different. They have been resampled and saved as new images. Why? can anybody explain and tell how I should do to avoid multiple copy of my texture images, in my exported Collada file?


Because they are now different images; The source that will be repeated across the face has been distorted. I’m not 100% sure, but I doubt that a Collada file can contain the information that would be needed to replicate the distortion - the only way to get *that *specific texture with *that * specific distortion is to generate a new image and reference it rather than the original source.


If I not use the texture->position to adjust the texture with. But instead copy the surface with the first texture and then make the adjustment on that copied surface. Then I get the preferred visual result and without the extra texture image in my .dae-file. So it must be some thing that SketsUp is missing. I can’t explain it in other way or am I missing something.


I hand made a simple .dae-file to confirm the possibility to adjust without resampling. Here is the result
adjustedTexture.zip (76.3 KB)


What transformations are you performing on the texture?
Looking into Collada, I think it supports scale, skew, rotate and transform functions for textures, but if you use ‘pins’ and deform the texture (so that each side of the texture parimeter is a different size) then SU would have to generate a new texture.

I also found this: Export dae creates hundreds of duplicate materials when it should only be one


Thanks for the research. It seems to be a lot comments about texture uv-mapping but no real solution to it. I think it is a pity that this problem still exists considering the amount of people that have talked about this problem.
A texture can easily be duplicated, in the .dae-file, by just making a copy of a surface, with a texture that has been tilted. Manually I can make a .dae-file that has all scale, skew, rotate adjusted without resampling, so I think it wouldn’t be so hard to fix this problem, inside SketchUp. Now is just only annoying problem, in otherwise a very good program.


I had an idea about this. I thought about exporting as FBX, hoping that it would have UV mapping, and then to try Autodesk’s FBX Converter to make the Collada file. But, SketchUp exports separate images with FBX, and OBJ too.

So, it’s not specifically a Collada issue.