topic Re: How to create surface or solid to model existing tunnel in Civil 3D Forum

How to create surface or solid to model existing tunnel

samir_rezk — Sat, 26 Jan 2019 01:43:04 GMT

Hi,

I am wondering about thoughts to model an existing tunnel, I have 3D Polylines resembling contour data at the ground, side and top elevations of a tunnel; I could possibly get the point cloud for the tunnel as well. I tried creating Civil 3D surfaces from each layer and then extracting solids from one surface bound by the next layer above it but it keeps crashing.

It may be more useful to use AutoCAD modelling tools to create a solid out of the data but I am not sure how to go about doing that - loft command didn't work so well for me!

Any help is greatly appreciated - thanks

Re: How to create surface or solid to model existing tunnel

neilyj666 — Sat, 26 Jan 2019 09:57:46 GMT

i don't know the answer but you won't create a Civil surface from this as there will be overlapping areas but you may be able to create a lower and upper surface and use these

Re: How to create surface or solid to model existing tunnel

Jowennl — Sat, 26 Jan 2019 13:26:17 GMT

Hi @samir_rezk,

I would recommend you not to convert this current data to a surface and solid as it should be created from the source model. If this is an existing as-built tunnel then ask the surveyor to give you top surface and bottom surface. You may ask the point cloud and create the surface your self as the last option. The attached sample 3d polyline overlap each other and would be very hard to know if converting this to surface tin is accurate enough.

Anyway, I still did try to convert a portion of this tunnel as an exercise. See attached animated gif and dwg.

Some guide images and comments below:

Data as tin surface feedback.pngConcept of tunnel surface creation.pngPortion by Portion Approach.pngSurface to Solid.png

Cheers,

Jowenn

Re: How to create surface or solid to model existing tunnel

Anonymous — Sat, 17 Jul 2021 05:04:37 GMT

Hi guys! I have a similar problem but my solution was to take the 3D polyline’s and whit help of command LOFT create surface. After that I used a command SMOTH and when it’s finished whit processing data I exploded the geometry and created TRM, but it was divided in upper and lower tunnel surface.

But my problem is how to compere TRM surface of tunnel and point cloud from scanning?? To get a section preview as you can get if you create alignment and then compare 2 or more surfaces and display it in section preview???

p.s I have Recap and I converted a LSA file to a recap…

can someone help me???😞😞🙂