Inconsistencies with offset curve

Hi everyone!

I am trying to create a pitched roof for my building by lofting by offsetting my base curve, moving it up on the z axis and then lofting my two curves. I had no problems with this method and submitted it for my assignment.

However, upon redownloading the file, the offset curve tool just doesn’t seem to work anymore? Is there anyway to fix it so I can prove it worked? And is there another method I could use instead of offsetting? (To adhere to the parameters of the assignment I can’t use any plugins unfortunately).

Thanks, any help is much appreciated!

(Btw I can’t figure out how to internalise the data so i’ve put the component in question in the indigo box outline laballed ’ low roof’)

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Hi -
That seems to be working fine here:

I’m not sure where you intended to internalize, but the attached file has all the other stuff removed and the initial curve internalized after the Polyline component.
To internalize, right-click and pick “Internalise data”.
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Which version of Rhino are you running?

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Without having looked at your code, but having used Offset extensively:

You cannot always guarantee in which direction the offset happens. It depends on the direction of the curve. Therefore if you want to build something that is pretty universal, ie. you can assign different curves and pretty much know it will work you do the following:

For the offset distance input your value AND the same value in the negative. Then measure the length of both output curves and take either the longer or shorter one. That way you know for sure which offset you got and can prevent mistakes.

Also be sure to provide a plane to the offset component, even if it is just in XY plane (the default). It can prevent a lot of errors.

Lastly - especially if you are using polylines - I would recommend Clipper. It is a far more reliable offsetting algorithm. Just be aware that it only does Polylines and not Nurbs curves.

Hope that helps.


I’ll have to bring this up with my lecturer as they reported the initial problem, in this case it’s possible they’re running an earlier program as I modelled this in rhino 7.

In that case this is an extremely simple fix! That make a lot of sense how internalise data is used, I was picking apart the menu tabs trying to find them.

Thanks for all the help!

I’ll keep that in mind when I adjust the curve geometry later!

I’ve seen clipper pop up before in regards to offsetting but wanted to try out the offset tool first. Thanks for the recommendation though! I think from now on I will just be using that.