I have two zero thickness surfaces that I want to merge together to create one solid object. The front part I can easily extrude to the required thickness but to join the curved surface at the back (left on the pictures) to the flat surface below seems to be more difficult as the vertices need to be extruded to different heights
Any help or suggestions would be much appreciated.
IT has not, but it appears he’s using 2.49 anyway.
Anyways, how did you end up with so many vertices?
It would be easier to join them with a simpler model.
In the select menu there are other options for selecting vertices.
Try out the edge loop, and ring.
Select Non Manifold might help, but it’s hard to say with .stl.
Try out Non Manifolld, CTRL SHIFT ALT< +M
For reducing the vertex count on this type of model, I’d suggest you use retopo to rebuild a new mesh on top of the old one. That way you can easily match the top to the bottom.
I would rough out a low res mesh to the same outline as the model, extrude it to form a top and bottom face, then retopo or shrinkwrap the top face of the new model to the top mesh, and the bottom face to the bottom mesh.
EDIT: Also, looks like you are modelling a shoe sole, so think about making the heel flat to start with, and then extruding it separately out of the bottom face of the sole. Otherwise you will end up with some very stretched mesh around the join between the sole and heel. Extruding an object with a step in it can be very troublesome otherwise.