problem importing sketchup models into t3d?

#1 I am not familiar with sketchup -- I use Blender, but I have had issues like this if the model consists of separate pieces and the materials are not set in the Torque's material editor. Also if you have some of the faces pointing the wrong direction you will have missing faces in Torque. You can test this out by going into Torque's material editor and changing the materials of the model to double sided. If this does fix the problem then you need to fix the faces in the modeling program and re-export the model so that you do not have to have each material eat up unnecessary frames and draw calls. It will save you issues later on as well if you ever decide to animate the model or set the model's collision to visible mesh.

#2 I'm not sure about sketchup or blender, but in 3DS Max, you should try out the OpenCOLLADA plugin to export DAE's.

If the model still doesn't show from exporting with that, make sure you collapse any modifiers and try again (some are fine, eg. the skin modifier). I've found that some modifiers either don't export properly in a COLLADA format and/or T3D can't import right.

As for textures, I don't know if i'm doing something wrong here, but I havent been able to get PNG's or JPEG's to work. So I save my textures as DDS for importing (these also work nicely in 3DS Max)

#3 I've posted on your other post. You need to set up the models in a particular way. Can you include some screen shots of in modelling package / sketchup and torque and I'll try and help as I've used the pipelines fine.