Print Page | Close Window

3D Tunnel Model

Printed From: CAD Forum
Category: EN
Forum Name: AutoCAD
Forum Description: Discussion about AutoCAD and AutoCAD LT, viewers, DWG and DWF formats, Design Review, AutoCAD 360, add-ons
URL: https://www.cadforum.cz/forum_en/forum_posts.asp?TID=7522
Printed Date: 16.May.2026 at 23:35


Topic: 3D Tunnel Model
Posted By: john1951
Subject: 3D Tunnel Model
Date Posted: 16.Mar.2012 at 10:04

Hello

I need to create a 3D Model of a tunnel in AutoCad.  I think that the  tunnel should be made of 1 or more surfaces, and that a 3D polyline 

should be the center line of the tunnel.  The 3D pline should be composed of lines and arcs, with the arcs tangential to the lines, like the center line of a road.  

I also need to determine the shortest distance between any x y z point inside the tunnel model, 

and the nearest wall (surface) of the model.

I have experimented with SWEEP using a straight 3D pline and a semi-circle.  The first problem is that snap to nearest does not work as expected on the swept surface, it only snaps to certain lines on the surface.  The second problem is that I don't know if it is possible to create a 3D polyline as described, like a road centerline.


Thank you

John


Replies:
Posted By: John Connor
Date Posted: 17.Mar.2012 at 17:32
Why 3Dpolylines?  What exactly are you constructing?  Why surfaces and not solids?


-------------
"Humans have a strength that cannot be measured. This is John Connor. If you are reading this, you are the resistance."

<<AutoCAD 2015>>

Posted By: john1951
Date Posted: 17.Mar.2012 at 21:28
Hello
Thanks for writing back.  I need a 3D model of a tunnel in national grid coordinates.  I need to model surfaces because I want to connect a laptop to a surveying instrument so that when I measure a point inside the tunnel while it is being constructed, I can compare the measured point to the design surface.   In order to see if the tunnel has reached design location at any measured point.  The model does not have to be based on a 3D polyline, but tunnel and road design is generally based on such a line.  I am beginning to think that it may be necessary to use AutoCad Civil 3D.  I would prefer to use AutoCad, if it is possible.

Thank you
John    

Posted By: John Connor
Date Posted: 17.Mar.2012 at 22:09
I think you would be better off using Civil 3D.

-------------
"Humans have a strength that cannot be measured. This is John Connor. If you are reading this, you are the resistance."

<<AutoCAD 2015>>


Print Page | Close Window