A Plane is a flat surface used in CATIA as a surface on which you can sketch. Planes can be useful in surface design where more complex shapes require the use of planes. Planes can be defined in a number of ways;

- Offset from plane
- Parallel through point
- Angle/normal to plane
- Through three points
- Through two lines
- Through Point and line
- Through planar curve
- Normal to curve
- Tangent to surface
- Equation
- Mean through point

The Plane icon can be found in the “Reference Element” toolbar, and looks like this;

After selecting this option, you should see the following dialogue box;

You may find that it is frustrating at times when CATIA tries to be helpful by trying to automatically detect what type of plane you are attempting to create. By clicking the green padlock, it allows us to prevent an automatic change of plane type whilst selecting geometry.

**Offset From Plane**

As the name suggest, this plane type creates a plane which is offset from the reference plane;

Ticking the Repeat object option after OK allow the user to create more offset planes, with each plane separated from the initial plane by a multiple of the offset value.

**Parallel**** Through Point**

This plane type creates a plane on a reference plane and a point. Once a reference plane is selected, a plane will be created at the selected point with reference to the plane.

**Angle/Normal to Plane**

In this plane type, the user will have a choose a reference frame and a rotation axis. By increasing or decreasing the angle, the plane created will make an angle with reference plane. Tick ‘Project rotation axis on reference plane’** **if you wish to project the rotation axis onto the reference plane.

**Through Three Points**

In this plane type, the plane will be created based on 3 points. The plane passing these 3 points will be created.

**Through Two Lines**

In this plane type, the user can create a plane passing through two lines. If the lines are non-coplanar, the plane will be built on the second line. CATIA does this by virtually translating the line vector of the first line till it intersects the line vector of the second line. The user can also tick ‘Forbid non coplanar lines’ so the previous method does not apply.

**Through Point and Line**

In this plane type, a line and a point are needed to create the plane.

**Through Planar Curve**

In this plane type, the plane containing the selected will be created.

**Normal to Curve**

In this plane type, a plane normal to the curve will be created. By default the plane is created at the curve mid-point. To select a different part of the curve, create a point on the curve and select it as the point when on the plane definition. Alternatively, you can automatically select either end of the curve without having to create extra points

**Tangent to Surface**

In this plane type, a plane will be created tangent to the selected surface and point.

**Equation**

In this Plane type, the plane will be created by inputting an equation to the programme. The equation is in the standard form of Ax+By+Cz=D. The user can also select a point to replace D as the distance away from the origin.

**Mean Through Points**

In this plane type, the user select 3 or more points to create a mean plane through these points. The user can edit the plane by removing or replacing one of these points.