Are faces for bodies defined in a particular order?

[dirktheeng]

I am to the poitn now where I want to start building more com plex geometries and like any good model, I want to start defining new sketches on existing faces.  So my question is, how do I know which face to grab based on the index?  Or rather, what is the logic in the ordering of faces in the list? Is there any?

[dirktheeng]

The same question could be asked about profiles in a sketch.  How do I know what the index is to the profile I want other than guess and check?

[ekinsb · Accepted solution]

You shouldn't rely on the order for any of the B-Rep entities or profiles.  I'm not sure how a certain order would be very useful anyway.  However, I do understand the problem that you're trying to solve because constructing a model with more than one feature typically involves using geometry that was created in previous steps.  There are several ways to find the geometry of interest.

1. Some features support intelligent grouping of the created faces.  For example, the ExtrudeFeature object supports the startFaces, endFaces, and sideFaces properties that return specific faces created as a result of that feature.
2. All features support the faces property that returns all faces created as a result of that feature.
3. You can interrogate the geometry to find the goemetry you're intersted in.  For example you can find all faces of a particular shape or faces that have a normal in a specific direction, or faces that have a certain range box, etc.
4. Some functionality planned for the future is a way to do a programmatic select.  For example, you will be able to specify a point in a space and get back entities that are within a speciified tolerance of that point.  You will also be able to specifiy a point and a direction and get back all of the entities intersected by the defined ray.