Drop Curb where there shouldn't be.

[AllenJessup]

I'm modeling a parking lot. I have Featurelines and a few added points to define the surface. I model the bottom face of curb and the top back of curb. I draw the face of curb then use Stepped Offset to create the top.

In one area the surface is ignoring the top of curb. This is happening in the curves that help form the ends of the islands. It looks like in the area of the cubs, the top of cub grades drop to the bottom of curb elevation. If I had done this on purpose they would make nice drop curbs. But I need the top of curb grade.

I can force it to follow the top by inserting multiple elevation points. But I think it should be following the elevation of the featureline.

I'm attaching a picture. The plan is north up the page. The model view is looking northeast..

Allen Jessup, Rockland County Highway Department

Civil 3D 2011, Version 2
Windows 7 Pro, 64 bit

Dell Precision T7400, Xenon X5460, 3.2 GHz, 4 GB Ram
NVIDIA Quadro FX 4600, 768MB - Driver Version: 8.17.0012.6570

[Joe-Bouza]

Hi Allen, are you setting mid ordinate to a small number like 0.05?

[AllenJessup]

I tried giving the TOC FL a higher priority. That didn't work. I turned on the Surface Points and it looks like there were no points grnerated fro the bottom but the grade was somehow extended and overrode the top.

[AllenJessup]

Hey Joe.

No. I left it at 1.0, which hasn't given me trouble before. I can try recreating it with a higher Middle Ordinate.

Allen

[Jeff_M · Accepted solution]

I've found that you need to use a midordinate value of 0.02-0.05 to get decent results when working with smaller radii.

[AllenJessup]

That's it. I'd just recreated the surface with 0.03m and it looks much better around the curves.

Is there anywhere you can change that for an already built surface. I'd rather not have to recreate all the edits I've done for the surface I already have.

Thanks.

Allen

[jmayo-EE · Accepted solution]

The smaller the radius, the smaller the midordinate required in my experiance.

I typically use 0.1 for radii less than 5and 0.01 for radii less than 3.

Watch these values on large data sets though, they can bloat a surface/dwg.

If you see this happen on a tangent, add a Supplemental Distance.

[Jeff_M]

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@AllenJessup wrote:

Is there anywhere you can change that for an already built surface. I'd rather not have to recreate all the edits I've done for the surface I already have.

Thanks.

Allen

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I wish.....can't even write a prgram to do it, as it is a read-only property.

[jmayo-EE · Accepted solution]

I wish.

Take the feature lines that you want to redefine. Move them to a new site, copy them back to the old site and then delete the new site. The feature lines are now removed from the surface and the copies can be redefined.

Jeff's numbers will work fine too! I should hit F5 more often. 😉

[AllenJessup]

Thanks for letting me know Jeff.

[AllenJessup]

Good workaround John. I'll have to tackle that next month. It's almost vacation:30 and I have other fish to fry in the next couple of hours. Luckily we're running a detour route through this parking lot that will be in effect for the next 3 month. So the design won't be needed until then!

Allen

[jmayo-EE]

Enjoy the time off.

[JeffPaulsen]

Another way to remove the breaklines from the surface is to erase them and use the OOPS command to bring them back into the drawing. Then you can redefine them with the proper midordinate value.

[jmayo-EE]

Thanks Jeff!