terrain Cross section of the 3D terrain

[Andrej Skvarca]

Hi guys,

 

I've created an AutoLisp app which creates a cross section of the 3D terrain grid. The terrain can consists of raw AutoCAD entities: MESH / POLYFACE MESH / POLYGON MESH (one or more, even combined).

 

As an author, I will be grateful for any comment, especially suggestions for improvements and developments.

 

Andrej Skvarca

TERRAIN_CROSS_SECTION.fas

[ammobake]

This is pretty neato

 

In terms of terrain modeling for civil projects, Civil3d has built in features to do all of this.  But the terrain can sometimes be obnoxious and not as simple as importing survey data.  So there are sometimes manual error corrections you have to do on the mesh just because of how autocad renders the surface.

 

But if you have a good mesh that has relatively decent detail this might be a good option for Autocad users.

 

Also gives you really good idea of material needed for your cut/fill (i guess in this case for like a foundation wall or driveway).  Because you could pretty easily get the volume of fill material for different applications.

 

One could also incorporate a basic UI and upload this as a standalone app in the autodesk app store.

 

There used to be a way to import terrain data from google earth with the surface photo overlayed as a material.

But don't know what ever happened to that (used to be free).

 

You could then draw in your foundation, foundation walls, etc.. in 3D and use this for your foundation/foundation wall sections.

 

-ChriS

Edited April 28, 2021 by ammobake

[ammobake]

There is a way to use drone photos to create a terrain model but cant' remember which program does that.

[Andrej Skvarca]

Yes, drone photos can be used to create a terrain 3D model, but accuracy is much much worse than laser-lidar scaning, nevertheless this is now used very often, e.g. for defining surface changing and calculating volume of landslides and other changes of terrain, examing urban areas... There are quite a lot of photogrammetry software, some are free:
https://all3dp.com/1/best-photogrammetry-software/

 

Andrej

[Andrej Skvarca]

1 hour ago, ammobake said:

This is pretty neato

 

In terms of terrain modeling for civil projects, Civil3d has built in features to do all of this.  But the terrain can sometimes be obnoxious and not as simple as importing survey data.  So there are sometimes manual error corrections you have to do on the mesh just because of how autocad renders the surface.

 

But if you have a good mesh that has relatively decent detail this might be a good option for Autocad users.

 

Also gives you really good idea of material needed for your cut/fill (i guess in this case for like a foundation wall or driveway).  Because you could pretty easily get the volume of fill material for different applications.

 

One could also incorporate a basic UI and upload this as a standalone app in the autodesk app store.

 

There used to be a way to import terrain data from google earth with the surface photo overlayed as a material.

But don't know what ever happened to that (used to be free).

 

You could then draw in your foundation, foundation walls, etc.. in 3D and use this for your foundation/foundation wall sections.

 

-ChriS

 

Ammobake, thank you for useful suggestions!

Andrej

 

 

[BIGAL]

Doing a section of a TIN has been around since the 80's, there are a number of free TIN modelling tools out there some do sections and cross sections. Eg EZYSURF, one from here by YMG

 

;;****************************************************************************;
;; Version V0.5.8                                                             ;
;; C:TIN, Generates Delaunay Triangulation and Voronoi Diagram.               ;
;; C:CONT, Generates Contours from a sset of 3DFACES.                         ;
;; C:GEN, Generates a bunch of points for testing.                            ;
;; C:DEMOZ, Demo of locating yourself in a triangulation.                     ;
;; C:LBL, Generates Label on Major Contour at regular spacing.                ;
;; C:FLBL, Generates Label on All Contours along Fence Lines.                 ;
;; C:DLBL, Generates Label Dynamically (Based on Alan JT routine)             ;
;; C:PROF, Generates a Longitudinal Profile.                                  ;
;; C:XSHAPE, (Chi-shape) Generates a concave boundary around triangulation    ;
;;                                                                            ;
;; Added triloc,   ymg                      August 2013                       ;
;; Added getz,     ymg                      August 2013                       ;
;; Added demoz,    ymg                      August 2013                       ;
;; Modif setup,    ymg                      September 2013                    ;
;; Added get_tin,  ymg                      October 2013                      ;
;; Added c:flbl,   Alan J Thompson          October 2013                      ;
;; Added c:cont,   ymg                      November 2013                     ;
;; Added c:dlbl,   ymg                      November 2013                     ;
;; Added c:ocd,    AUGI Forum               November 2013                     ;
;; Added c:prof,   ymg                      February 2014                     ;
;; Speed Optimization mainly in Contour        March 2014                     ;
;; Added c:xshape  ymg                           May 2014                     ;
;;****************************************************************************;

 

I am not trying to discourage but you may be reinventing the wheel. It is a problem for people like me that have been using CIVIl design software software for like 40 years and also sold and supported Civil design software for many years. So many people just do not want to pay for anything, the commercial software does so much more and its price has fallen dramatically, and major players like BRICSCAD are looking at this very seriously as a market to compete with CIV3D. 

[Andrej Skvarca]

Thank you Bigal, I appreciate your reply. You have right about reinventing... I've yust enjoy prgramming again after a long pause and I couldn't stop till something comes out.

Andrej

[BIGAL]

The next step is walk along a pline and do cross sections at spacings.

[ammobake]

lol you gotta jump over the cracks!

 

For anyone interested in taking a deep dive into terrain modeling in civil3d i recommend checking out this doc.

https://cdn.ymaws.com/www.njspls.org/resource/resmgr/Docs/TerrainModelingContouringAna.pdf

 

If you follow the step by step you'll actually learn some neat stuff.

No idea if that civil3d training company exists anymore.

 

-ChriS

Edited April 30, 2021 by ammobake

[BIGAL]

That is a very good tutorial old fashioned paper copies sometimes are easier than the Utube version.

 

Alternative software are going to a more online movie tutorials. For CIV3D and Bricscad.

[Andrej Skvarca]

I'm also thinking about point clouds, are there already tools for creating sections, contour lines and other useful things from point clouds in Autocad?

 

Andrej

 

[BIGAL]

Autocad MAP and CIV3D support clouds, as do other 3rd party civil add on, point clouds are becoming a nightmare with point cloud of Millions of points. The old TIN might have like max 100,000 points. I have loaded clouds in the 250Mb size others are bigger. 

 

A freebie trim clouds program would be more useful. Often a cloud is like 1km wide but you only need 250m wide following a pline. I would suggest .net solutions.

[Andrej Skvarca]

Beside point clouds, which are imported usually from .LAS files, ASCII point files are still used very often (txt, xyz, csv, etc...). This kind of files can be imported in Autocad as point entities, you don't need MAP and CIV3D, instructions are here:

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/sfdcarticles/sfdcarticles/How-to-import-a-list-of-coordinates-into-AutoCAD.html

 

But I think that more useful than points entities are polyface mesh (eg better visualization,) Autocad command for that is 3DMESH and you still don't need MAP and CIV3D. Trouble is, that 3Dmesh command first reqiure number of rows and columns and coordinates of corners:

Number of vertices in M direction (between 2 and 256):
Number of vertices in N direction (between 2 and 256):

Position of vertex (0, 0): 
Position of vertex (0, 1): 

....

 

Solution:

 

Make SCR file as explained in link above from Autodesk knowledge. You get something like that:

_MULTIPLE _POINT
9231.55,8799.44,10
9241.83,8781.49,20
9194.23,8765.63,20
.....

 

Excute this script, count rows and columns of point entities (you can count rows and c. with Erase command and Fence selection with NODe snap). Than erase all points. Replace first line in SCR file and again excute script command:

_OSMODE 0 _3DMESH 241 181

9231.55,8799.44,10
9241.83,8781.49,20
9194.23,8765.63,20
.....

 

In this example, 241 is the number of rows (vertices in M direction) and 181 is n. of columns (vertices in N direction).

 

Yes, I know that with MAP, CIV3D, SpatialManager and other commercial apps, even for a few dollars, you can do that. But if you need solution fast, without tedious searching, selecting  and downloading, learning of menus and rules and if you got that kind of project once in a decade, simple and free tools like mine (TERRAIN_CROSS_SECTION) or some other free LISPs (more versatile than mine) can be useful.

 

Andrej

 

 

 

TERRAIN_CROSS_SECTION.fas