3D Polylines

Gabriel Bell
Gabriel Bell
in 3D Modeling

First, I realize my question is probably about as elementary as you'll find in this forum, but I am relatively new to Bricscad. What little exposure I've had has been for Land Surveying, where 3D is of little or no use. Plus, I’m just not that bright. Anyway, I am creating a linework file in V7 which is to include 3D polylines.

Is there a command to create 3D arcs? All I’ve been able to do is create straight-line segments in 3D and I really need to be able to create arcs along the polyline. Any help is greatly appreciated.

Comments

  • Damian Harkin
    Damian Harkin

    3d polylines cannot include arcs.  2D polylines can.  You might just draw simple (separate) lines and arcs in 3D.  An arc which is not 'lying flat' will look like an ellipse in plan view.  A curve which is truly circular in plan but has a slope has to be a helix!  You may have to approximate this as many short line segments.

    AutoCAD/Bricscad entities are not really designed for Civil Engineering requirements such as road centrelines.  A road centreline may need clothoid transition spirals in plan view at the same time having a parabolic vertical curve in long-section view.  To get this functionality you may need a Civil Engineering add-in program or some other software like 12D Model.

  • Dirk Van Thienen
    Dirk Van Thienen

    hello Gabriel,

    Our land surveying GeOpus application for BricsCAD has functions to create 3D arcs and even create 3D offsets. But these polylines are always segmented. So actually the arc is computed in small segments and heights are interpolated.

    Another way but very tedious is to first make a UCS using 3 points and next draw the arc using the same 3 points. This would result in real arc's but actually 3D rotated in space.

    With GeOpus it is also possible to convert 2D curved polylines in to 3D if every vertex of the polyline has a point with elevation. But again arcs (bulged polylines) will be segmented in small straight segments.

     

  • Rakesh Rao
    Rakesh Rao

     

    Hi Gabriel,

    Yet another add-on for Bricscad (and AutoCAD) which can create 3D arcs, along with linear 3d elevations interpolation is our GeoTools application.

    You may want to check this out. Let me know if you need more info.

    - rakesh.rao@4d-technologies.com
    - www.4d-technologies.com / www.coordsys.com
    - Blog:EN: http://rakeshrao.typepad.com
    - Blog: ES: http://kiranabhat.typepad.com

This discussion has been closed.