I am Yaşar, you won't probably remember me. I just occasionally skim read this forums. I see that some people having difficulties exporting dae files in a way that hpl will see it, I have some experience in subject, so I wanted to share my experience with people.
First thing first, read http://wiki.frictionalgames.com/hpl2/thi...3d/blender
%80 percent of the time, that will work. But sometimes it doesn't. It is not because it is wrong, but it is because it doesn't mention some little details.
First thing to take into account when exporting is, correctly U.V mapping the texture. Adding texture to material without U.V mapping will NOT work, it will just crash your model viewer.
Also, before adding texture to your models, save your model (blender file) to where textures resides (It is better if they all in one place.). And use relative paths when adding textures instead of absolute paths, then export your dae to same place. So that you can easily port your models from one place to another (Always keep dae and textures together.). If you don't do that, you will probably fail at some point when trying to move your models from one place to another.
Sometimes, when you export your model and see it in model viewer, you may see that texture is shown "inside" of the model, not the outside (look really weird)! That is because normals of your model is mixed up. You should go back to blender and flip the normals and export again. This should solve your problem.
And also, one should remember always to use textures with sizes of exponents of 2 (256x256, 512x512, 128x1024 etc.) Otherwise it will either crash your model viewer, or just look awkward.
One last point to remember is that, materials you create might be mixed up when you create it and one material accidentally get linked against 2 different geometries (or datablocks, or vertex groups... whatever one calls it). If this happens without proper care (accidentally), your model will not export correctly. Will look funny in model view.
You can export rotation/location/scale animations without problem, however, I couldn't export shape animations correctly into dae format (because blender's collada export sucks! Not actively developed.) If anyone can do it and post the method, it would be great to learn about it.
And also, do not try to export armature/bones, because as far as I can say, that doesn't work either. If someone could do it, I also want to hear about how to do it.
I hope this will help some people. Best Regards,