Reference Planes
Use a reference plane to sketch somewhere the model has no face. Select the geometry it should be built from, press P, and set the number that positions it.
A reference plane draws no material. It is a place to work: a support for a sketch, an axis source, a mirror plane, an input to a pattern.
The five kinds, and what to select first
The selection you make before pressing P decides which kind you get.
| Kind | Select first | What you set |
|---|---|---|
| Offset from face | One flat face | A distance, and Flip to send it the other way |
| Three points | Three vertices or reference points | Nothing — the points define it |
| Midplane | Two faces, or two reference planes, or one of each | Nothing — it lands halfway |
| Angled from face | One face and one edge of it | An angle. The edge is the hinge |
| Tangent to cylinder | — | An angle around the cylinder |
Tangent to cylinder has no selection that reaches it. Kapy cannot tell a flat face from a curved one from the selection alone, so it never guesses this one. Make any plane, then change the Variant row at the top of its panel to Tangent to cylinder and pick the cylinder.
The rules each kind enforces
Each kind refuses the input it cannot use, and says which:
- Offset from face needs a flat face. A cylinder's side gets you Reference geometry requires a planar face here.
- Three points needs three distinct points that are not in a line. Two on top of each other, or all three in a row, and there is no plane to build.
- Midplane needs the two faces to be parallel. Anything else gets Selected faces must be parallel for a midplane.
- Angled from face needs the edge to lie on the face, or run parallel to it. An edge from the other side of the part cannot hinge anything.
Those messages appear in English whatever language the editor is set to.
Distance, angle and Flip
Distance is in millimetres and takes a parameter or an expression like any other number in Kapy. It can be negative, which puts the plane on the other side of the face. That is the same thing Flip does, and either is fine.
Angle is in degrees, positive one way and negative the other. Neither field is clamped: type 900 mm and you get a plane 900 mm away, floating well clear of anything you modelled.
Hiding one
Reference planes are drawn much larger than the part they hang off, so a document with four of them is hard to see through. Turn Visible off in the panel and the plane stops being drawn while everything built on it keeps working.
A hidden plane cannot be clicked either. Turn it back on when you need to pick it again.
See also
- Reference Axes and Points: the other two kinds of reference geometry
- Using References: what to do with them, and what breaks when you delete one
- Creating a Sketch: sketching on a plane once you have one