Originally posted by Zappy:

A shape key name of "upper_lid" in Blender means that that shape key will be active when both the "upper" and "lid" flex controllers are used in Source, if exported from Blender as a DMX model. The same applies to any other shape key names featuring underscores.


If you don't want such "corrective" flexes, either replace the underscores in the shape key names with hyphens or such (e.g. "upper-lid" instead of "upper_lid"), or get fully rid of the underscores (e.g. "upperlid" instead of "upper_lid").

It worked! Thanks a lot and thanks for the quick reply!

I got my model with a bunch of shape keys (42 in total) working in Blender, but exporting the mesh as .DMX and compiling the model only results in only 5 of them showing up in SFM.
When exporting as .DMX again, I observed the system console displaying a warning about a "corrective shape key" for every shape key. This is one of them:

"Warning: Found corrective shape key "upper_lid", but not target shape "upper""

Also, in Blender under Flex Properties (under Source Engine Exportables), it tells me that I have 5 shapes and 37 corrective shapes, which I think may be part of the problem.

Exporting the mesh as .SMD then compiling the model results in the model being stretched out and distorted in SFM.

I will be grateful for any help or advice on this. Thanks in advance!