Inkscape wizardry

Let’s say I have a simple box:

Then I want to make a special corner on this box:

How do I join these lines, so that the new corner is one complete line? Figuring out this side of inkscape is a major source of headache and deep existential worries…

@scrounge79 - are you around? I’m sorry to bother, but I know that you are the head wizard in this department…

Exactly the kinda thing I’ve been looking for a CAD program that would let me do simply!

Haven’t gotten in to it yet but some blurbs give me hope for Carbide Create.

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Usually I’ve exported such a scenario to bitmap, and then retraced - and voila! But I’d reaally like to figure out how to do this the “right way”, in terms of combining vectors to a complete segment.

I think what I’d really like is a very simple program that would let you choose to add what capabilities you want rather than some of the amazingly capable programs that have so many capabilities to begin with I can get lost in them too easily.

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Draw a rectangle, draw a separate circle and place it over the corner, select both shapes, do a “difference” operation to subtract one shape from the other. If it chops up the wrong shape try selecting one shape first, then the other shape… Order selected matters, can’t remember exactly which way is which.

I like librecad for real simple 2d cad. Especially dimensionally specificied flat parts. Inkscape is geared toward artsy stuff.


I really like the “ruler” function in sketchup. You define a distance, a parallel line, or whatevery, and you make new shapes based on these constraints. In Fusion you have to add the constraints afterwards, in inkscape you don’t have similar functionality. Maybe I should check out librecad? 2d CAD program sounds about perfect :smiley:

Yes, these functions are what I’ve been trying out. But it’s really hard to keep the head straigth with all the nodes and lines and keeping things complete. I sometimes open them up in estlcam just to see if I get any errors, as incomplete shapes… I wish it was possible just to drag the nodes unto each other, and voila.

Try merge paths?

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Hmm, sounds very obvious… I’m sure I’ve tried it, but I don’t remember right now why it didn’t work. I think librecad would be much better, as you say.

Hello youtube, old friend, show me your things!

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FreeCAD can do something like this pretty easily. I would be happy to give some details if you’d like.


LibreCAD is sort of “dimensions first”. You need to say, "Make a box from 0,0 of size 100,200. Then, make a circle of radius 50, at 50,50. You have to know most of the dimensions before you start. This is how autocad used to work (before 3D).

Freecad, onshape, fusion, solidworks all take an approach where you can just make some shapes and then define what constraints you have (which us sometimes the size of a rectangle, or the radius of a circle, but it is sometimes just parallel, or a distance, or tangent stuff). Any of those are focused on 3D, but there’s no reason you have to have to make anything in 3D. Just stop at a sketch. Fusion can’t export dxfs anymore though.

All you have to do is convert the lines to a path then join the nodes. At that point you can also move any nodes you need to in order to clean up your design like those little tips comong off the straight lines for example.

I’m sorry I have been negligent on this forum. You all are keeping the MPCNC alive and I have not had time to keep it rocking. I guess Inkscape is my forte here.

Two ways.

As @kyle point out. You can do a boolean operation to put a radius to a corner. Draw you rectangle and then a circle of the radius you need.

Select both and do a Path > Difference

The other way is to tweak the nodes of the corner to make a radius you want. It gives a bit more control. You can select nodes of two path objects that are open ended and join them, or you can add two nodes and then tweak the handles to make a shape you want. Add some nodes and then make a radius as needed in node edit mode (F1)

Add two nodes up and to the left of the corner node. Then delete the corner node. Grab the handles and make the radius as you need.


Thanks a lot, all of you who replied - and always nice to see you @scrounge79! As you say, the forum is really growing and acting great. I’ve been quite busy myself the last months. I manage to keep an eye on some topics, but I’m not able to reply much…

Thanks for all the Inkscape input. It’s a bit embarrassing to see how easy such tasks can be solved. I guess it’s something about the whole vector way of doing stuff that causes brain hiccups…


I didn’t find a good way to do exact measurements when adding nodes and tweaking them to get the corners and radiuses right.

So I ended up with the suggestion from @kyle , making the shapes I wanted to exclude, and using Exclusion. That let me cut the corners precisely according to the plans, turned out great! Thanks a lot.

I gotta say though - that inkscape is not the most intuitive tool when it comes to making 2d cad. I’ll dive deeper into the suggested tools next time I’m dealing with something similar.