Since I’m not really sure what it is you’re doing or wanting to do, other than “use really large textures”, I’m just going to explain what rhino does when it loads textures…
But first, I’d like to point out that “size on disk” does not equate to “size in memory” for file formats that use any form of compression. Also, texture dimension size limits do not really equate to physical memory limits (i.e. loading files that fall within the hardware limits can still fail simply because they’ll take up too much of the remaining memory). Lastly, Rhino does not work with paletted images, it will convert any image data less than 24 bits into 24 bit data. In other words, Rhino only uses 24bit (RGB) and 32bit (RGBA) image data.
- Rhino loads the image information from the file…
If the load fails (for any number of reasons, which can be memory limits, or limitations imposed by the library Rhino uses to process image files), then usage of that texture fails, and Rhino does nothing.
If the load succeeds, the image dimensions are compared against the hardware limits, and if they fall within those limits, the image data is pushed up onto the GPU where it sits, waiting to be used.
If the dimensions fall outside the hardware limits, Rhino resizes the image data to match the hardware limits (paying attention to aspect ratios), using a simple halftone downsample method…and then the resized data is pushed up onto the GPU where it sits, waiting to be used.
With that said, if you have a situation where a texture isn’t working, then most likely it’s because step #1 above failed… And if I were to guess, it would most likely be because of the limitations of the 3rd party imaging library Rhino uses…but I would need to run some tests to really figure it out.
If you have an example that fails for you every time, please post it here and I’ll be glad to take a look at it and try to provide more insight on what’s actually happening.
Given that, I am curious why you’re using such large textures, and what it is you think you’re getting from using larger resolution textures? I understand that higher resolution images give you much better fidelity in the display, however, after a certain point, that’s no longer the case, and increasing texture resolutions will result in no change in the final display output (with the exception of large zoom factors).