So I've been using FreeCAD (and CAD in general) now for about a month or so designing mounts and such for 3D printing. I have a reasonable amount of 3D modeling experience in Blender but am absolutely loving parametric modeling where you can simply change your mind on the length/dimension of something after the fact and just change it and the whole 2D sketch and 3D model adjust accordingly.
One problem I'm having is this concept seems to only apply to 2D and not 3D since sketches are 2D. What I mean by that is I create my sketch in 2D, fully constrained with dimensions but than I have to extrude it to bring it into 3D. When I extrude it, I have to specify the forward and backward extrusion length and possibly move/translate the 3D extrusion along the extrusion axis. For these extrusion lengths, I have to figure out the numbers in my head with additions and subtractions. Worse, since most parts I'm making are boolean unions of multiple 3D extrusions that butt up against one another, If I do decide to change one of them at some point, I have to change the extrusion lengths and possibly the translations of any of the neighboring/butted up against parts. This seems to me a big gaping hole, a pain and against the spirit of parametric modeling.
What would be absolutely awesome is you could make a 3D extrusion using 2 sketches on separate planes (probably 2 orthogonal planes) without specifying forward/backward extrusion lengths or a movement/translation across the extrusion axis at all. You're effectively extruding using a planform and a profile sketch. The idea would be to select these 2 2D sketches on different planes, click the "dual sketch extrusion" button and you get your 3D extrusion. Technically, what this button would do is extrude both sketches into infinity in both directions and take the boolean intersection of them. Right now to accomplish this, I have to manually extrude both sketches using some large extrusion lengths (as an approximation for infinite extrusion) and manually do a boolean intersection.
Is there some way to already accomplish this that I'm unaware of? Should I make a feature request of this? Is there some other way to do extrusion with specifying hardcoded extrusion lengths and hardcoded translation/move lengths? See the attached screenshots and file to see what I mean.