Creating Features - Intergraph Smart 3D - Reference Data - Hexagon PPM

Intergraph Smart 3D 2D Symbols

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English
Product
Intergraph Smart 3D
Subproduct
2D Symbols
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Reference Data
Smart 3D Version
13
SmartSketch Version
11

Features are symbols that are used to add or remove material. They are operations performed on structural parts and are small and insignificant to strength analysis. There are three types of features:

  • Sketched Feature – Small holes such as air holes and drain holes located at a point on the face of a part.

  • Edge Feature – Small holes such as rat holes, drain holes, and water stops located on or referenced off of an edge of a part.

  • Corner Feature – Corner snipes and scallops located at the corner of a part.

Each feature has a corresponding Place Feature command in the software.

The software places feature symbols by mapping two coordinate systems. One coordinate system is defined or implied in the symbol file. The other one is a coordinate system that is created by the Place Feature command in the model. These two coordinate systems are matched at placement time. Therefore, vertical and horizontal constraints can be used in feature symbols because they stay vertical and horizontal in the symbol coordinate system.

Feature symbol shapes MUST be a closed contour. For example, when an edge feature meets the edge, the shape must be extended beyond the edge and be closed to execute the cut properly. The same rules apply to corner features.

Feature symbols must be created in the positive U-V quadrant.

Sketched Features

Sketched features are essentially small holes that are not significant for strength analysis.

The sketched feature symbol is a very basic symbol. It does not require any graphic inputs be defined in the symbol file. The (0,0) origin point of the 2D Symbols file is used as the default placement point for the symbol. The symbol geometry should be defined about the 2D Symbols file origin point and constrained using horizontal and vertical constraints in such a manner as to get predictable placement results.

When placing a sketched feature, the user selects the placement point in the Draft2D environment. This point becomes the origin of the local X-Y coordinate system that is mapped to the symbol coordinate system. You can then rotate or flip the coordinate system to set the symbol position.

Edge Features

Edge features (small drain and rat holes) are symbols that are placed or referenced off the edge of a structural part. The edge feature can, but is not required to, cut (intersect) the edge itself. All edge features, whether they cut the edge of the part or not, must be defined as a closed contour.

When the user places an edge feature, a placement point is located along the edge of a part in the 3-D environment. The normal and tangent vectors to the edge are extracted at the placement point and these vectors become the local X-Y coordinate system. The X-Y coordinate system is always placed with the X-axis tangent to the curve at the placement point. This coordinate system is mapped to the symbol coordinate system to orient the edge feature at the placement point.

In order for the symbol to map correctly, a point and a curve must be defined as graphic inputs in the symbol file.

Corner Feature

The software can handle two types of corner feature symbols. A simple round scallop placed at the plate corner does not require any graphic input. However, more complex scallops and snipes require input edge curves in order to compute their shape properly. Thus, some corner features require graphic inputs; others do not.

Corner Features Without Graphic Input

The construction and placement rules for a corner feature without graphic input are similar to sketched feature symbols. The key exception is that the placement point located by the command is exactly in the corner of a plate or profile. The user has no control over the X-Y orientation of the symbol. Thus, a corner feature without graphic input is only good for the simplest geometry like a round scallop.

The feature origin for a corner feature without graphic input must be at (0,0).

Corner Feature with Graphic Input

Most corner features contain more complex geometry than a simple round scallop. The more complex corner features will require graphic input from the software to correctly compute the geometry. The graphic inputs consist of two B-spline curves, which represent the curves from the 3D environment that form the corner of the part and define the U- and V-axes of the symbol file.