Take this as an example.
Here is a curve wound on a cylinder (pipe) and projections patterned in such a way that the projections are normal to the pipe.
In the example the curve has been wound using the WRAP command.
Let us say you need 5 instances in the pattern meaning 4 pitches.
Create a point pnt0 on the curve at 0.1 ratio.
NOTE: pnt0 is the mother point and all features requiring reference pattern should be referenced to pnt0.
Pattern this point at an increment of 0.2 (0.2*4+0.1+0.1 = 1)
To create a feature at point pnt0, we need a plane.
Create a Datum plane thru point PNT0 and TANGENT to the Pipe surface.
Select the pnt0 as SKETCH REFERENCE.
Create your feature.
Group the feature along with the Datum plane. Now pattern as a REFERENCE Pattern.
You may also refer to the following link.
http://www.youtube.com/watch?v=i5t4xSk06_w
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