Make sure the version of SMD tools you are using matches the version of blender.

You might also want to check to see if your model is normalized. You can ensure this by first positioning/scaling your model properly, and then press ctrl+a and select "location", "scale", and "rotation". You can check to see that this worked by pressing "n" and checking to see if all the location/rotation values are 0 and all the scale values are 1 (under the Transform subheading). Then re-export your .smd file.

It worked, thanks so much.

Np, good luck.

Ok, sorry about this but now in the ingame preview, part of my model is transparent, i've checked my textures, they are all solid, and in blender its all considered one object and I don't see any difference in any way. Do you have any idea of why this is happening?

Can you show me a screenshot of the vmt settings you used? Just print screen > go to imgur.com and paste the image.

Ok, that might be the problem, considering I don't know what VMT settings are :P, how do I see them?

The in-game importer has a screen that shows you the vmt settings (it's the material editor).

http://imgur.com/PoXIfKH here, i can get the blue one if you want too

Hm... everything looks right to me. Is your hat paintable? If it isn't, make sure to uncheck the "Paint VMT1" option in the previous screen. Otherwise you might try enabling the "Base Map Alpha Phong Mask" option.

Lastly, you can try saving your .tga file without an alpha channel (and save it as 24bits/pixel).

None of those options seem to be working, would a photo of the actual transparency issue help? Also, I use gimp so that might have affected something.

Gimp must be the problem. It's gives so many problems with alpha channels-- it's unreal. Did you try exporting your image as a .tga but making sure to uncheck "RLE compression"?

Yeah I did, nothings changing

When you say transparent, do you mean that you can partially see geometry? Or is it completely invisible? If it's completely invisible, recalculate your normals in Blender: ctrl+n to recalculate normals. Then re-export as a .smd.

http://imgur.com/p4qjvYw I mean transparent as in this

Doesn't look transparent to me. It looks like your normals are flipped. 3D faces can only be textured from one side (usually), so normally what you want is for the texture to be facing outwards. In your case it appears that your texture is applied to the reverse faces. This is easily fixable. In blender, recalculate your normals as described above (you can check to make sure your normals are correct by going into texture mode and seeing if any faces are textured backwards). You can also manually flip your normals for certain faces by selecting the faces you want to flip and clicking "Flip Direction" under the Normals subheading in the Mesh Tools toolbar (in edit mode).