My mesh object has missing faces! D=

[Rolig Loon]

If I had to guess (and I do have to guess, since I can't see your model), I would guess that some of the faces in your Blender model have flipped normals.  It's a good idea to always work with Backface Culling switched on so that you can tell whether you are looking at the front (visible) side of each face or the back (transparent) side.  You can also make face normals show if you're really unsure.  Then, if you find individual faces that are pointing the wrong way, select them and flip normals.

BTW, rather than upload a model just to see what it looks like in a trial version, do your work on the Aditi grid.  Uploads are free there.  You can't bring anything back to the main grid (Agni), but you can do a lot of testing there until you are comfortable enough to pay for a final upload.

[Rolig Loon]

If I had to guess (and I do have to guess, since I can't see your model), I would guess that some of the faces in your Blender model have flipped normals.  It's a good idea to always work with Backface Culling switched on so that you can tell whether you are looking at the front (visible) side of each face or the back (transparent) side.  You can also make face normals show if you're really unsure.  Then, if you find individual faces that are pointing the wrong way, select them and flip normals.

BTW, rather than upload a model just to see what it looks like in a trial version, do your work on the Aditi grid.  Uploads are free there.  You can't bring anything back to the main grid (Agni), but you can do a lot of testing there until you are comfortable enough to pay for a final upload.