Shape Bender twists object when bending

I read that the extension had issues in some later versions, but I’m having problems in Sketchup Pro. 2018.

I’m trying to bend a toothed belt around a pair of pulleys. Here’s the object I’m trying to bend with the target path. The reference path is under the belt, right on the red axis.

bend belt|690x364

It almost works, but for some reason the belt is twisted. Here’s what it looks like:

I’ve trying using the up and down arrows, but nothing is presented like I want.

Also, if the belt is longer, SU 2018 crashes.

Is there a way to do this in SU2018? SU file attached.

bender test.skp (464.5 KB)

Two things. You need to set things up correctly. Stand the belt up on edge and change the axes so they are aligned with the model axes. (Explode the belt segment and make it a component after its up on edge.

Layer the curve down on the ground plane. Yours needs to be redraw so that all the edges run the same direction. I drew it working counterclockwise from the bottom.

With the right setup Shape Bender will work fine.


Thanks! So, the bend has to be in th xy plane, not the yz plane. I only read that the reference line had to be along the red axis.

Actually, I ant the teeth of the belt on the inside of the curve, but I’ll play a bit with the belt on edge to see if I can get it work


I couldn’t tell that from your setup Set up the flat belt segment appropriately.

Does the extension try to scale the object if the reference line is not the same length at the curved line? Some of the teeth (surprisingly, not the end ones) got stretched a lot. when I did it.

It will stretch or compress the bent shape to match the length of the curve. If you don’t want that to happen, you need to make the curve the same length as the straight line and the component.

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Ok, stupid question then. How does one go about making a curved line a specified length?

You can find out its length by selecting it and looking at Entity Info. Don’t weld the arcs to the straight segments. Then you can select parts of the overall curve to see their length and work from there for the ends.

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Worked great! Thanks!

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Something to keep in mind if you are wanting to make toothed belts, it can be easier to place the teeth rather than bending the belt.
There are various component stringers available.
Here I have used a simple one, Path Copy.
Path copy