Greeting,
I have a 3d polyline at the bottom and want to extrude to a fix elevation(6 m). Is there a command to do that? I tried to create another surface at the elevation of 5m and use it to trim the original surface. However, it doesn't work for me.
Any help would be appreciated.
Hi Qixing,
More details please. What end result are you needing this for?
Dave
Dave Stoll
Las Vegas, Nevada
This is not possible you CAN NOT have a x,y=x,y with different z values there must be a slight transition. There must be a slight lean so that x,y,z=x-.001, y-.001,z
Rick Jackson
Survey CAD Technician VI
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Are you referring to Civil 3D surfaces or vanilla CAD surfaces - same names but very different?
neilyj (No connection with Autodesk other than using the products in the real world)
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Qixing,
I still haven't figured out what you're going to do with it.
Copy your 3D polyline @0,0,6. Convert the new 3D polyline to a 2D polyline and change the Z to 6 in properties. You can use that to trim the "curtain".
Dave
Dave Stoll
Las Vegas, Nevada
Hi @qchenTPPXV, You can use the command OFFSETFEATURE. This works with polylines, 3d polylines, parcels, featurelines & survey figures. You will have to add an offset distance because like what others have mentioned you can not have sheer vertical faces within Civil 3d surfaces, but you can specify something really small like .01. We typically do this for curbs, walls, exposed slabs; just situations where we need something vertical but with a slight angle. Make sure you offset towards the inside of your 3d polyline.
After selecting your horizontal offset, you can now specify your vertical offset, you have the choice of: Slope, Grade, Difference, Variable or in your case Elevation.
In the picture above, I just converted the 3d polylines to feature lines and used those to define the surface. The bottom feature line has varying elevations, but the top is all set to one constant.
Yes, I tried to use this method.
To trim, first select the surface then the 2D polyline at 6m, but for select the area to trim it doesn't work. I select the upper part of the curtain but didn't get it.
@qchenTPPXV @Pointdump the screenshot shows a vanilla CAD surface - these can't interact with a Civil 3D Surface; as I stated previously same name but very different objects and you cannot use the vanilla TRIM editing tool.
neilyj (No connection with Autodesk other than using the products in the real world)
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