CST2013: Structure Editing Overview

The structure definition, as described in the Shape creation overview page, allows the input of structure elements. However, the structures usually need to be edited afterwards. There exist, in general, three different ways to modify existing structures: Editing the History List, Editing the History Tree, and performing Local Operations on the model.

Editing the History List

The History List stores all macro language commands for each creation step.

You may edit the shapes in the History List by just selecting the corresponding line and pressing the Edit button. Afterwards, you may modify the commands directly.

Pressing the Update button in the History List will finally re-generate the modified structure.

Editing the History Tree

A very convenient way to change the shape parameters of existing shapes is to select a shape and choose the Edit Object Properties from the main menu or Properties from the context menu.

If the selected shape is still a basic shape, the shape creation dialog box for the particular shape type will open automatically and show the shape’s current parameters. You may now edit the parameters and press the OK button to re-generate the structure with the modified shape.

If the edited shape is the result of one or more boolean operations, a so called History Tree window will open. The tree shows the construction history of the selected shape, including the generation of basic shapes, transformations and boolean operations.

You may now select a particular basic shape or transform operation from the History Tree and press the Edit button. Now, either the shape creation dialog box or the transform dialog box will open. You may now edit the parameters and press the OK button to re-generate the structure with the modified parameters.

Local Operations on the Model

Editing the structures with either the History List or the History Tree requires the presence or parametric information. However, for imported models from other CAD systems, this information usually is not available.

On the other hand, sometimes only small modifications are necessary to a shape produced by complex operations. In such cases, it may also become complicated to perform the desired change by altering the elementary shapes.

In cases where some elements of the model need to be modified directly, there are two modes to help to complete this task:

• Modeling: ToolsModify LocallyModify Face: Three operations are offered:

• Offset face:  This operation moves the surface in the normal direction in each point of the selected face

• Move face:  The selected faces may be moved by a translation vector. This operation will sometimes fail if heavy topology changes occur because of face translation.

• Remove feature:  Activating this command will prompt the program to attempt to remove the selected faces. The resulting gaps in the model will be automatically closed by extending the neighboring faces. The operation will fail if the model is not closed by face extensions.

• Modeling: ToolsModify LocallyDefine Face Constraints: Even though this feature is designed for defining sensitivity analysis parameter, especially setting the radius of cylindrical faces might be of great help for editing imported models. Three definitions of constraints are offered (see Define Face Constraints for a detailed description):

• Set distance to plane: A fixed distance between one of the principal planes and the selected faces is defined. Internally this is done by moving the faces.

• Set distance to point: A fixed distance between a base point and the selected planar faces is defined. Internally this is done by offsetting the planar faces.

• Set radius: Selected cylindrical faces are set to a given radius. Internally this is done by offsetting the faces.

Examples

In addition there are some more operations for applying structural changes to existing shapes:

• Modeling: ToolsShape ToolsFill up Surronding Space: This operation creates a new solid that fills the entire calculation volume. You will obtain a new shape in which all shapes defined thus far are completely embedded. In a manner of speaking, this action creates a ”negative form” of your structure.

• Modeling: ToolsShape ToolsSlice by UV Plane: Cuts shapes into two new shapes. The cutting plane is the uv plane defined by the local coordinate system.

• Modeling: ToolsShape ToolsSeparate Shape: Splits shapes with separate bodies.

• Modeling: ToolsShape ToolsMerge Materials of Component: Makes a single shape for each material of the selected component .

Face Healing

There are various editing possibilities concerning faces and curves of a selected shape. A curve represents an edge that does not necessarily belong to any face. For example, sometimes the surface representation of imported shapes may be corrupted such that one of the following operations may be helpful in repairing and further editing the elements.

Clean Shape: (Objects Solid Healing ToolsClean Shape) This operation removes all unnecessary faces or edges from the selected shape.

Face Operations: These operations are used to modify single face elements.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingDelete Selected Faces: Deletes a selected face.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingCover Edges: Fits a surface over a closed loop of curves or edges.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingLoft Edges: Creates a face by lofting two edges.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingSkin Edges: Fits a surface through a series of curves or edges.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingSweep First Edge Along Second: Creates a planar face as a rhomboid between two adjacent dangling edges.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingReverse Selected Faces: Inverts the normal orientation of a selected face.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingReverse Faces of Selected Shape: Inverts the normal orientation of all faces belonging to the selected shape.

• Modeling: ShapesFaces and AperturesShape from Picked Faces: This operation creates a solid from the selected faces.

Curve Operations: These operations are used to create curve elements which belong to the selected solids.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingAdd Linear Curve Between two Points: Creates a linear curve between two picked points and adds it to the currently selected shape.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingAdd Tangent Curve: Creates a tangent curve between two points, each belonging to an own edge and stores it within the selected shape.

• Modeling: ToolsShape ToolsHealing ToolsModel HealingSplit Edge at Point: Splits the selected edge into two parts, determined by the position of the picked point on the edge.

 Shape Healing

Use the healing operations (Modeling: ToolsShape ToolsHeal Shape) and (Modeling: ToolsShape ToolsHeal All Shapes)) to repair imported shapes.