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Message 1 of 10 (4,185 Views)

Converting arcs to polylines

4185 Views, 9 Replies
05-10-2012 07:29 AM

I have some polylines that mark the edge of roadway and around the curves there are arcs in the linework. How do I turn the polyline with arcs in it into a polyline with vertices, say, every .5' or so along the curve and turn the curve into a polyline? I tried the pedit and using decurve but it doesn't work well.

Using C3D 2012

Thanks

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Message 2 of 10 (4,180 Views)

Re: Converting arcs to polylines

05-10-2012 07:46 AM in reply to: dibr0804

Convert it to a 3D polyline and then convert it back to a 2d polyline. Unfortunately you can't control the spacing.

Out of curiosity, why are you needing this? perhaps there's a way to use the polyline with the curve instead of converting.

Brian Hailey
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Message 3 of 10 (4,178 Views)

Re: Converting arcs to polylines

05-10-2012 07:51 AM in reply to: BrianHailey

I want to set the polylines as boundaries but it seems to work better if the arcs are taken out and actual polylines

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Message 4 of 10 (4,175 Views)

Re: Converting arcs to polylines

05-10-2012 07:54 AM in reply to: BrianHailey

Converting it to a 3d pline is kind of what Im looking for, but it messes up the line and makes it cross in a bunch of places.

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Message 5 of 10 (4,170 Views)

Re: Converting arcs to polylines

05-10-2012 08:22 AM in reply to: dibr0804

What kind of boundaries? Would you be better off using FeatureLines? They support curves and when use in a surface either as a breakline or boundary you can densify the curves by specifying a middle ordinate in the definition.

Or if you truly need a polyline you could make it into a FeatureLine with densified curves then explode the FL and join the resultant lines into a polyline

Allen

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Message 6 of 10 (4,161 Views)

Re: Converting arcs to polylines

05-10-2012 08:44 AM in reply to: dibr0804

If you are referring to boundaries in a surface, leave it as an arc. If you want more "tessalation" in the surface, lower your mid-ordinate distance (available when you create the boundary). The default is typically 1' (or 1m). I find 0.1' to work well.

Brian Hailey
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Message 7 of 10 (4,159 Views)

Re: Converting arcs to polylines

05-10-2012 08:48 AM in reply to: dibr0804

Who says you can't control the spacing's of the vertices?

1st, convert arc to polyline.  Use the command mapclean and select all the arcs you want to convert but don't select any of the commands. Hit next until you reach the cleanup methods page and check "Arc to polyline".  Now your arcs are polylines.

2nd, add vertices. Under modify in the ribbon and under "Edit Geometry", you will see a command "Insert PI".  It'll give you an option to add vertices by distance or increment.

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Message 8 of 10 (4,136 Views)

Re: Converting arcs to polylines

I think if you use the Add Vertices tool you will have to select each arc one at a time won't you? If you convert the arcs to featurelines, set the tesselation values (mid ordinate setting) and explode them you can do it all in one batch.

Also if you are not familiar with Map Cleanup, Qselect and Pedit can also convert the arcs to Plines, but you can skip that step altogether if you convert the linework to Featurelines.

Neil Wilson (a.k.a. neilw)
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Message 9 of 10 (4,115 Views)

Re: Converting arcs to polylines

05-10-2012 01:42 PM in reply to: BrianHailey

I never tried setting the oridnate distance.. that probably would have worked... I just dont like using the arcs because the surface will get bounded further away from the line than I want. I want the line to be the boundary not a few feet from the arc.  Kind of hard to explain but I just went around and traced the arcs with a polyline.

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Message 10 of 10 (4,082 Views)

Re: Converting arcs to polylines

05-11-2012 06:10 AM in reply to: dibr0804

Yeah. It is hard to explain. Below is how I handle this with FLs and a boundary. The magenta lines are FeatureLines, bottom of curb at face and the top of curb at the back. What is hard to see is the blue line just behind the back of curb FL. This is the boundary of my surface. I created it by offsetting the FLs that describe my outside boundary, exploding them and joining them into polylines. Then I manually close any gaps and form a single outside polyline boundary. If I need to add vertices in specific palaces, I use the Insert PI command.

This woks well and creates a nice surface and a good looking model. Everyone will develop a method that works for them. I do try to convince people that FeatureLines are a good thing. One of the things I like about them is that you CAN have arcs. The only reason I explode the offset FLs is so I don't have to have a separate site to keep them from interacting with other FLs. Theoretically they shouldn't since they're the outer boundary. But if you have to extend the area your creating the surface in they might cause trouble.

I decided to attach the image because you can't see if very well in the post.

Allen

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