Set Cplane to object doesnt give me expected view

Last time I used Cplane creation I was getting the hang of it.
Today…not :frowning: , I am in default cplane and world top mode… in perspective view I have a simple rectangle with a circle on it, in top view it is a single line angled top left to bottom right.
In front view it is a rectangle with an elipse…because I am viewing it obviously at an angle to its face.

I want front view to give me a view perpendicular onto that rectangle so I see a circle.

I choose Set Cplane to Object and select the rectangle in perspective view, the front view doesnt change, though the grid in perspective view is now aligned to my rectangle. I seem to recall the views top front and left should update.
so I right click front view title and choose set view front, but nothing changes.

so I come out of this, choose View undo cplane change and nothing changes in perspective view, still the grid is aligned to my rectangle, so I repeat that command and this time it reverts to how it was.

Lets try setting C plane instead via an ortho window…and use front view window.
select set Cplane to object, select my rectangle in Front view and the grid changes in perspective view, it aligns with rectangle, but still front view shows no circle, only an elipse.

Just how do I get Front view grid to align to rectangle and see there my circle as a circle, as one would expect if looking perp at the rectangle with circle on it ?


Use the Plan command to view any CPlane head-on.


Hi Pascal,
in fact Left view as opposed to Front is the view that should be my rectangle with circle, so correction to my post made.

However, I have again chosen set Cplane to Object, selected my rectangle in perspective view, the grid realigns to it, then activated Left view window, typed plan and chosen plan command and still no change in left view.

try again, nothing.

aha. try something different. I am expecting that if I select the object in Perspective view, then the ortho views will update to reflect this change,…that doesnt happen. My brain expects it to.

why doesnt it, I bet I am not alone in this.

so now I choose set cplane to object and this time activate left view and select it in that view, yet nothing changes.
then I run Plan command and behold, now I see my circle.

Whilst rhino is intuitive, I find Cplane anything but !

and I am sure others hit this mental issue.

Where can I go to get the complete low down on Cplane and rid myself of these expectations that dont happen ?


Try setting “Universal CPlanes” in Options>Modeling Aids --Mitch

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Have you tried cplane 3 point Steve? It gives you more control. I’ve created an alias for it.

When you set the cplane, try to set the red x-axis first as parallel to the world x-axis as you can, then set the y axis so you’re picking up the face you want. I wonder if there are any videos out there on the subject, it definitely is a task (like gumball) that is easier to demonstrate visually than explain verbally.

I use Infinite Skills tutorials quite a lot as they’ve have pretty good (well to a newbie like myself) tutorials. See for tutorial of remapping and c-planes. Hope this is relevant.

A few things to note that haven’t been mentioned yet:

  1. Your Cplane and View are independent of each other. Changing the Cplane does not in any way change the view of the active viewport.
  2. Each viewport can have a different CPlane, so if you change the Cplane in say your perspective viewport, that has no effect on any of your other viewports.
  3. Plan, which Pascal mentioned is indeed very useful, but it’s mostly useful when you want a “top” view of a non standard Cplane - something that has been rotated at some weird angle or the like. For what you’re trying to do, you don’t need it.
  4. Level I Training guide.


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Hmm- then I completely missed what Steve is after- I thought he wanted to look straight on at a custom CPlane.


It can if as Mitch suggested you set the construction plane behavior to Universal CPlanes, which it sounds like Steve is after. If Universal CPlanes are set, then the view will also update when the CPlane is set if the view is parallel.

Thanks Helvetosaur!

 I usually don't use that Universal C Planes setting and it must be the default and for a couple months since an update that has been driving me nuts. Who knew! I work mostly in single view perspective and have a alias that Pascal gave me ages ago to mirror across the XZ plane. I design boats and yachts so mostly everthing is bi-laterally symmetrical. I set the cplane to faces in Perspective to work on say bulkheads in the YZ plane and to mirror across the centerline I find it easier to CTRL-TAB to the Top plane and hit my alias and then keep cycling through back to the Persp window. Needless to say with Universal C Planes turned on this was all messed up. Probably a bad habit anyway but old habits are hard to break. Now at least I am back to my normal viewport behaviour, thanks again.

Yeah you might be right. Hard to say really…

that did the trick. Cheers