Wirecut doesn't honor cplane axes

Hi all,

If I set a cplane, then try to use WireCut, the dialog options for what direction to run the cut don’t honor or match the active cplane. Here’s a screenshot, and an example file. Try to use the line to cut the box, along the cplane’s Y axis, and this is what you get (it’s using the world Y axis).

Let me know if I’m missing something!

I’m seeing this in the WIP, but it’s also present in rhino 8. (current WIP: Rhino 9 SR0 2026-6-30 Rhino 9 BETA, 9.0.26181.12304)

wirecut-axes-example.3dm (115.0 KB)

According to Help for WireCut that is the intended behavior. It’s been that way since at least V5.

Ah. Too bad. I guess I’ve only recently noticed it since I started using it more aggressively in combination with cplanes. I guess that changes this from a bug report to a feature request – would be nice if it were possible to follow the active cplane axes.

IMO that would be a more sensible default, since it’s really easy to reset the cplane to world coordinates, and if you never make/use cplanes you’d never notice the difference…

If you want the wirecut to be parallel to the cplane, like this

then select the wire, select the object and then set the direction option to Pick and choose two points on the cplane y axis to set the direction, then carry on as normal.

Note that you can select the two pick direction points by entering co-ordinates (first = 0, second = 0,1) and these honour the cplane axes and in this case follow the y-axis. You don’t have to pick with the mouse.

HTH

Jeremy

Using “pick” is great, but often irritating in, for example, the project I’m working on now, which involves many perpendicular, interlocking ribs of plywood, to be cut on a cnc. Wirecut is extremely helpful for making cuts to the ribs.

The problem is that the X/Y axes of my ribs is different from the world X/Y. No problem, I use a cplane. But I’m going back and forth between editing ribs in one direction to ribs in the other, meaning I have to go through the “pick” dialog every time.

I stand by my “this should be part of the command” comment, but for anyone else looking for this, it can be achieved with a macro/alias, e.g. to cut in the cplane Y direction: _WireCut _Pause _Pause _Direction=pick 0,0,0 0,1,0

You could make an explicit request to have an option to Wireplane for using CPlane x/y/z directions as the cut direction. Such a request might be most effective as a new thread with a title such as “Request: WireCut Direction using CPlane” and a brief explanation of why it is needed.