Offset behaviour

Hi David,

The previous offset did generate unnecessary points, however its behaviour was rather consistent, and therefore one could find a way around this.

The revised offset component does remove these unnecessary points, however it also removes some necessary ones (see attached). For example in case of linear or partially linear plines, upon offsetting, the intermediate points disappear leaving only the end points.

This is very problematic for many definitions we have developed as, offset is a rather common component, and this invisible points carries critical information.

Offset also seems to add a single point in a pretty random position (see attached).

Ideally the number of vertices, whether you offset in or outward should be equal before and after offsetting and obviously based on the same vertices.

Any chance to have the component to maintain all existing points, at least as an option, would be greatly appreciated.

Many thanks

Ari

Attachments:

OFFSET.JPG, 38 KB
OFFSET.gh, 14 KB

Replies to This Discussion

Permalink Reply by David Rutten on February 16, 2014 at 2:01am

You're right, I shouldn't have reduced the curves to begin with, this could always have been achieved by putting a Simplify component after the offset. I'll take the functionality out again so it's like it was before.

David Rutten

david@mcneel.com

Permalink Reply by Arqitect on February 16, 2014 at 4:26am

Great, thanks David.

Alternatively, to save a component in some situations, maybe the reduce functionality could be kept as a non-default option with tag indication on the lower side, same as the CullPt component and others. Hopefully it won't affect its auto-upgrading.

Permalink Reply by Vicente Soler on February 16, 2014 at 6:43am

Any chance to have the component to maintain all existing points, at least as an option, would be greatly appreciated.

You can use the offset loose component for this. There are cases when a proper offset won't have the same number of segments as the original curve. For example, a rectangle with a small chamfered corner offseted to the inside will change from 5 segments to 4. If your priority is to keep the 5 segments, offset loose will do that but generating a self intersecting curve rather than a proper offset.

Permalink Reply by Arqitect on February 16, 2014 at 7:00am

Offset loose doesn't work for me, particularly with closed curves.

Obviously equality of vertices before and after offset, applies only if the corners don't node out.

Basically, standard offset behaviour on most CAD platforms, nothing less nothing more.

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