Offset & EAP not coincicent

[Benson Shaw]

Seems like the offset is in error when applied to a spline or bez. Arc and corner point polys seem to produce true offsets. This manifests in VW2012 and earlier versions of Vectorworks.

Or are offsets not expected to be constant distance on normal to splines and beziers? Something about control point definitions?

Just curious.

-B

Also,"Vectorworks" gets a dotted red misspell cue in forum text boxes.?!

[Miguel Barrera]

I believe that offsets for splines and beziers are converted to polygons instead of polylines. So, how close they match a true offset depends on the resolution of the conversion in the preferences.

[Benson Shaw]

Thanks for considering this, Miguel

My test does not confirm your suggestions:

An offset of a spline curve yields a polyline with bezier points.

An offset of bezier curve yields a polyline with bezier points.

Toggle of 2d conversion setting in VW prefs Edit tab does not increase or decrease the difference between offset and expected "true" offset represented by endpoints of Duplicate Along Path or edge of EAP. A new conversion setting does not affect trueness of existing or new offsets.

Or did you mean some different conversion setting?

I guess we need to be aware that spline and bezier offsets are not necessarily uniform.

Workaround:

Run the EAP and extract the edge(s) - Yields a NURBS curve with lots of new vertices - very close to coincident. Differences may be due to graphics card or display settings

Close but not quite true:

Convert the spline/bez path to NURBS and offset that - Yields a NURBS curve with slight differences from EAP edge.

sigh.

-B