topic Re: polyline question in Modeling

polyline question

ICEdevil — Wed, 21 Oct 2009 08:43:08 GMT

is there any way to delete points in a polyline?

i have some polylines imported from archicad, and they are made of hundreds of small line segments that define a curve for example...is there any way to approximate a curved line out of these?

Re: polyline question

Barry Kelly — Wed, 21 Oct 2009 09:13:41 GMT

Trace over it with a spline choosing every 10th or 20th node or whatever is necessary to get the curve to match.
You can edit (add or subtract) nodes to alter the spline if needed once you have placed it.

Barry.

Re: polyline question

ICEdevil — Wed, 21 Oct 2009 09:19:58 GMT

yeah...i started to do this with a polyline over the old one, to approximate the curves but it will take forever

magic wand doesn't help because it doesn't know how to "approximate"....so...i think the "manual" method is the only one...

Re: polyline question

Anonymous — Wed, 21 Oct 2009 19:21:15 GMT

One way to do it (still manual) is to explode the polyline into line segments, which will be grouped if auto grouping is on. Select the grouped lines and assign arrowheads to both ends (use circle "arrowhead") so you can see where the end of each segment is. You can then trace over picking as many or as few end points as you like.

HTH

Re: polyline question

Barry Kelly — Thu, 22 Oct 2009 02:52:16 GMT

I would create a spline first with three points - start of polyline, middle of polyline and end of polyline.
Then I would stat to add nodes to the spline (pet palette) so that it begins to match the curve of the polyline.
This way you just add as many nodes as you need.
More in the tight curvey sections and less along the straighter sections.
Barry.

Re: polyline question

Dwight — Thu, 22 Oct 2009 03:34:13 GMT

Magic wand a polyline using the linear segments with segment length method.

Selecting the appropriate segment length controls the accuracy of the magic wand overtrace.

EDIT: OOPS: missed a step:

Magic wand a spline to the polyline, delete the original polyline THEN magic wand a new polyline with tolerances as above.

Re: polyline question

ICEdevil — Thu, 22 Oct 2009 06:43:00 GMT

Dwight wrote:
Magic wand a polyline using the linear segments with segment length method.

Selecting the appropriate segment length controls the accuracy of the magic wand overtrace.

EDIT: OOPS: missed a step:

Magic wand a spline to the polyline, delete the original polyline THEN magic wand a new polyline with tolerances as above.

Amin to that
thank you