So I’m making a design on Onshape but I need certain pieces that aren’t actually downloadable cad files or on the public libraries. I don’t know how to make my own sketches or pieces either. I need a 1x2x1x27 hole c-channel and I only see 1x2x1x25. How would I find these customized materials without having to make my own? Does anyone have a library with these?
So I don’t know about Onshape, but to get that part in Solidworks, I would start with the 1x2x1x35 c-channel (STEP file available here if you don’t have it already), trim it to 27 holes long (by sketching a rectangle on a face of the c channel covering holes 28-35, then performing an extruded cut from that rectangle through the whole thing), then save that as a new part.
Probably a similar workflow is possible in Onshape - maybe others here with more experience in this area can offer more specific advice.