Modding Question - blank part

[Major Healey]

Hey all can someone help me please, I made a simple fuel tank to see if I could achieve something and learn to do the process, it shows up in the part panel where it should but its a blank square, if I try to connect it to something I get the two green connection dots but an empty space in between. Can someone please help me narrow it down to what step I mucked up, is it a model/mesh issue when I made it, did I do something wrong in Unity or I have got the .cfg wrong. Basically does anyone know what if any of those three steps would cause that. According to me Ive got it all right lol, but evidently not.

[EndlessWaves]

The two issues may not be related.

Common causes of this on the model itself are either incorrect scaling (the part is far too small or far too large) or material issues (e.g. any material after the first will cause it's faces to become invisible).

For the scaling you can use the GameObject menu in unity to create a cube. With the default rescaleFactor that cube is 2.5m on a side (the diameter of the largest fuel tanks). If your part is excessively small or large next to that then you need to rescale it. Either re-exporting from your model program at the correct scale, changing the import settings in unity (click on the model in the assets palette), using the scale field in transforms in unity or rescaleFactor in the config. Bear in mind that any scaling on the transform of the GameObject the part tools are attached to won't be exported (although children of it will work fine).

Fix the model first and see if the icon is fine then.

Icons seems to be rendered with all transforms set to their default state. This means offsets need to be in the vertex positions and additional scaling and translation factors should be collapsed using tools like Freeze Transforms in Maya and Reset XForm in 3dsmax. You can see what the icon will look like using the asset preview in unity (the small window in the bottom right when you click on your model in the asset palette).