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This is hard to explain, so I am going to upload a portion of the model I am working to help explain. In the model, I need to cut the wedge shaped tip of [Body, handle] from the upper wheel on [Body, inner reel] as well as a couple of other [Body, xyz] parts. I need the corresponding hole that is cut to have, say 0.6mm clearance on each side.
I know that I can just create another sketch with the proper dimensions, pad that and cut it from the parts, but since FreeCAD is parametric, I would think that there must be a way to do this in such a way that the cut is linked to the original piece so that if I change the size of the part, the corresponding hole will be resized accordingly.
I have asked over on the FreeCAD forums and I was told to use ShapeBinder, with no other instruction. I found the wiki page for that command and when I tried to use the [ShapeBinder] element as a cut, FreeCAD tells me that "Links go out of the allowed range" and then placed the resulting cut outside the scope of any [Body] element. Aside from that, it doesn't allow for the clearance I am needing - it just does the cut.
Any help would be greatly appreciated... even if it's just to say what I ask cannot be done.
I use the spreadsheet for parametric resizing and positioning etc. You can program formulas to calculate parameters like position, dimensions etc. Works like excel. To relate a parameter of a object to the spreadsheet you have to click the parameter and start with a '=', choose spreadsheet of the list and enter the related cell. Looks like spreadsheet.B1. If you close this the related value appears. If you change values in the spreadsheet everything related will be change too. Works not if you processed things to a combined part.
You got me to thinking and I did a search on formulas. Turns out, if I give the original sketch constraints names, I can use them in other sketches. Changing the original values then changes the sketches based on that sketch. Thank you so much!
I wish that I could do [Sketch006.Constraints.wedge_height + 0.6] instead of [Sketch006.Constraints.wedge_height + Sketch006.Constraints.wedge_offset + Sketch006.Constraints.wedge_offset] though! It wold be SO much easier! But it works so...
You might just have a units problem in your formula. Possibly you mean [Sketch006.Constraints.wedge_height + 0.6mm] ?
The spreadsheets method works, but is complex. Being able to do a "cut" with clearance is a feature I have often wished for. I think it would have to be added to the underlying 3D engine library that FreeCAD uses (who's name escapes me) though. I also wish they would fix chamfering and "thickness" tool for complex shapes in that library but it does seem destined to be.
I'm new to FreeCAD, so I haven't used spreadsheet yet. I will look at some tutorials on that, though, Thanks.
Spreadsheets can take a while to implement but if you do it at the beginning, things go much more smoothly and quickly. I will upload a file here and you can check how I organize my spreadsheet and corresponding sketch constraints. I go lazy at the end and didn't fully constrain some sketches so it isn't perfect but it gives you a good idea. I use the box above the value as a title then add that same title under "alias" in the value's box. The alias is what FreeCAD sees eg. "Spreadsheet.ValueA".
Let us know how it works for you. I add clearances using "Spreadsheet.ValueA + .5mm" as an example.