How to get feature dependencies via script?

felix_hahnlein

In the UI, you can see what preceding features a certain feature depends on.

How do you get that information via the REST API or a featurescript evaluation call?

Thanks in advance

caden_armstrong

Short answer: no.

Long answer:
You could

• Get the IDs of all selected geometry from the parameters of your selected feature
  
• Traverse the feature list, getting the feature id for each feature
  
• running an "EvaluateFeatureScript" query in the API, looking at qCreatedBy(featureId)
  Evaluate the results of that qcreatedby, and look at all of the geometry IDs, if any match your step 1 Ids, you have a dependency
  
• If you only want 1st level dependencies, stop there
  If you want the whole list of dependencies (dependencies of dependencies), you then repeat the process for any dependent features until you run down the list
  

Not an easy process, but possible...

caden_armstrong

Short answer: no.

Long answer:
You could

• Get the IDs of all selected geometry from the parameters of your selected feature
  
• Traverse the feature list, getting the feature id for each feature
  
• running an "EvaluateFeatureScript" query in the API, looking at qCreatedBy(featureId)
  Evaluate the results of that qcreatedby, and look at all of the geometry IDs, if any match your step 1 Ids, you have a dependency
  
• If you only want 1st level dependencies, stop there
  If you want the whole list of dependencies (dependencies of dependencies), you then repeat the process for any dependent features until you run down the list
  

Not an easy process, but possible...

felix_hahnlein

Thanks a lot.

Some subtleties for everyone who wants to do something similar:

• EvaluateFeatureScript will evaluate the featurescript with the rollbackbar-index indicated by the REST API call. The rollbackbar is at the end of the document by default. That means that geometric entities which have been used and effectively deleted by intermediate features, won't be returned. I think that in the official python onshape-client package, the rollbackbar parameter has not been exposed for the eval_featurescript function. I had to modify that part of the code to pass it through.
• qCreatedBy will return the Id of newly created, but not of modified geometry. However, modified Brep entities will get a new geometryId which can be referenced by features. So in order to trace which geometryIds have been "created" by which operation, you have to call qCreatedBy at every step of the feature list also for all preceding features. It's a double loop, so we call qCreatedBy O(n^2) times, where n is the total number of features.

At least that's how I got it to work in the end. I'm open to suggestions

caden_armstrong

You could also just suppress each feature in the tree and see what breaks as a result.
A less elegant solution, but might be effective.