## Geometric Rules

A rule defines the relation between two (sub) geometries.

A rule can be set both between 2 sub-geometries of the same element or between 2 different elements.

Parallel

Command: Prb_Parallel

- 2 parallel planes: 2 sides of a plate parallel to obtain a rectangular plate.
- A plane parallel to a line

Perpendicular

Command: Prb_Perpendicular

Perpendicular planes: For example to obtain a rectangular plate

Coincident

Command: Prb_Coincident

A plane flat on another plane: The bottom plane of an end plate on the upper cut plane of a column

This rule can also be used between a cylinder and a plane, a cylinder and a point,… Cylinders appear when we use rules on round tubes or bended profiles.

Concentric

Command: Prb_Concentric

Because the center point of a circle or the center-line of a cylinder are not visible, this rule exists to put circles or cylinders on each other.

This rule can also be used to set a line concentrix with a cylinder's axis (or vice versa).

Tangent

Command: Prb_Tangent

This rule can be used only in the following combinations:

- Plane vs Cylinder
- Line vs Circle

Equal radius

Command: Prb_EqualRadius

This is a useful rule to reduce the number of dimensions. For example a plate with fillets. One needs to set the radius of only one circle or cylinder, and with this rule all radius can be set equal.

The following rules are dimensions. Further in the manual it is explained how and when the values can be adapted.

Distance

This dimension is placed between two (sub) geometries.

Note! that this dimension is automatically also a parallel rule: we cannot, as it happens, define the distance between two geometries if they are not parallel. It would be therefore superfluous to make two planes or a plane and a line parallel when there is already a distance between them.

Angle

This dimension is placed between two (sub) geometries.

To place an angle can be time-consuming, for this reason we recommend to add only an angle dimension if there is no other possibility: If you can obtain the same result without angles, then execute it without angles.

An alternative for angle dimensions could be a sin/cos equation.

Radius

With this dimension you can set the radius of a circle or a cylinder.

# Geometries

These are all possible geometries that one can use in rules:

- Point
- Line
- Circle
- Plane
- Spline
- Ellipse
- Cylinder
- Helix (Diagrid)
- Cone
- Torus
- Sphere