Two Shears Breaking Polysurfaces

So I’m trying to do something really straightforward and encountering a strange issue. I’m doing two shears on some grouped geometry, resulting in a cavalier projection when using a front view.


This is the current model


First shear


And it completely breaks on the second shear.

There is nothing weird about the geometry, they’re just regular closed polysurfaces. Does anyone know why this is happening? It’s very frustrating and I don’t even know how to describe the issue. I’ve tried in both Rhino 6 and 8.

When shearing, make sure you enable “Project” in object snaps, so that you only shear in one direction at a time. Best to share an example file, that shows a before and after what you are doing. Images don’t tell that much, other than that I see it’s not the result you are after.

Hi Mitchel - that seemed to work OK here - angles not correct but the process worked - I think Gijs’ comment about making sure to project Osnaps seems like it might be the thing.

-Pascal

Thanks for the input. The problem I’m having is when trying to do it at these specific angles to get a cavalier projection.

image
First 30 degree shear from top view


And it works fine

image
Second shear from right view looks like it works fine…

And it looks like it works fine from rendered…

But the actual geometry is messed up, and it is messed up in make2D as well