What happens with patterns and preconditions?

S1mon

I'm noticing some behavior with @Evan_Reese's 3D Point where a pattern of points silently creates no point when "Location on curve" goes slightly over 1.0, and then any feature (say a plane) which is dependent on that point does weird stuff. Normally if you are entering a value into the feature, the precondition limits the value to [0...1.0]. It seems like when that value is set with a varying "linear" pattern, that the precondition doesn't do anything. (I'm just using the pattern to iterate through the features).

annotation { "Name" : "Location on curve", "UIHint" : UIHint.MATCH_LAST_ARRAY_ITEM }
isReal(vertex.curveParameter, { (unitless) : [0, .5, 1] } as RealBoundSpec);

I checked with a simple variable and a single point, and increasing from 1.0 to 1.1 causes the 3D Point feature to fail, but in a pattern, nothing fails, it just has very unexpected downstream behavior.

Is there some reason why patterns don't trigger the precondition tests? Do features need extra bounds checking on inputs to avoid this kind of thing?

Here's a really simple example:

Range set to 1, and the pattern works as expected


Here it is with the range set to 1.01, and the last point silently fails (although the FeatureScript notices show errors), but the plane does something completely unexpected.

Evan_Reese

No idea what's going on behind the scenes, but commenting here to come along for the ride while you find out.