Dear Francesco,
Unfortunately, there are no 3D model for the MPX2100DP (Case344C), however, there is a 3D model for the case 867C which is the same package and same size as the 344C, but with 6 pins instead (by removing pins 1 and 6, the package would be exactly the same).
Case 867C 3D STEP model: https://community.nxp.com/docs/DOC-100736
You can find the drawing of these two packages in the following links:
Case 334C: https://www.nxp.com/docs/en/package-information/98ASB14912C.pdf
Case 867C: https://www.nxp.com/docs/en/package-information/98ASB42797B.pdf
I hope the 3D model of the 867C can be useful.
