Make changes to a completed FreeCAD project.

I made, and printed, an Ikea pegboard hook in FreeCAD and my third version created from scratch is still not quite what I am after. All I want to do is lengthen the part that is perpendicular to the board, a small rectangel. It is about 70mm but it would work better if it were 75 to 80. Is there a way to strech it out in FreeCAD or do I have to do it again from scratch?

I did try to diasble some constraints and make changes but the pad never changed. [ATTACH]n16665[/ATTACH]

3rd Hook FC RTP.FCStd (32.8 KB)

Does your part have any filets or bevels? These can cause issues of not refreshing. Did you try refreshing, think it’s CTL R or a menu item. If that doesn’t work delete the filets and or bevels and then refresh. It should show the right length. Add the filets and/or bevels back.

My part does have Filets. As soon as I have an opportunity I will try you suggestion.

I removed the 73.15mm constraint . Added a vertical constraint at the yellow arrow then changed the 78.67mm constraint to 85mm. That extended the hook. This what your looking for? I believe it recomputed correctly.

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I might suggest a vertical alignment constraint in the purple area


Screenshot 2.png

Exactly, thanks much. I am still having a hard time with constraints; I get it down to three or four then it takes me a lot of trial and error to find those.

That worked and was actually pretty easy. I didn’t add the vertical constraint first so when I changed it to 85 I got a triangle because only that point moved. With the vertical constraint done first I can now stretch or shrink the horizontal distance at will.

Constrains can be hard, indeed. FreeCAD sometimes also changes a line direction, when the size gets changed afterwards. Try to set all non numercial constrains first. Like horizontal, vertical, parallel, 90°. Use “Equal”-Constrain where possible.

Also learn about blue construction lines. Those are live savers. Unlike setting a dimension between points you can even use the equal constrain on them. Like the suggestion @Larry Bowers made. You can use vertical on the dots, but you could also draw a blue vertical constrained line and set the distance. Two birds on stone.

A good way to avoid having tons of similar directed constrains is to use the spreadsheet.

Sit down (well you probably are sitting when using CAD) and measure or set the basic dimensions, angles and diameters and use these to create the model. Sometimes you over complicate stuff by having distances used as differences you otherwise would not require, when starting outside in.

A bonus is that you can use the same measurement in every sketch and any change will be done at the same time everywhere. Another bonus is that you now have names not dimensions. You can name stuff by type: e.g. “connector size with” and “connector width” along with height. No “What was 75,5mm again?”

On first glance this looks like naming to much work, but it isn’t. It saves you time as soon as you do more than a single sketch and a single extrusion.

If you want to change a dimension in a year, you open the spreadsheet and from the naming it is instantly clear where to change a dimension. It may not even your design, but you will know what to do.

But even during the creative project this is helpful for the same reason. You type in the names or select them from a list. No typo possible and when you try different approaches this is just faster than rethink about a specific dimension again. The result is basically. "I want this line to be the “ConnectorWidth” and not “How long was it again. Where are my notes…”

Very helpful advice, thanks. I did look at one video that discussed using the spreadsheet and I can sure see the benefits of using that. So much to learn.

Yeah, the spreadsheet isn’t needed for every project. If it’s a really small, simple design that’s a one-off, you can forego it. But, for most projects I find it is a big help.