You can spend a lot of money on contouring, the software tools for surface interpolation and depiction do not come cheap and even the ‘inbuilt’ AutoDesk options require a hefty investment in a ‘Map 3D’ or ‘Civil’ variant. But there is a very effective and low cost option which I have been using for some time now and it’s proved itself to be a good ‘fast and dirty’ fix for getting contours done: TheoContour.
Like all of the Latimer CAD family of tools this is based on the premise of solving a CAD problem, not a surveying one: there are no data tables to code, no CoGo computations to step over and the outputs are pure CAD entities ready for your next DWG based task. And of course all is in 3D from the start.
Let’s start by looking at the results:
This composite view gives you an idea of what TheContour is capable of: annotated smooth 3D ploylines and shaded surface generation.
So how does it work?
TheoContour is an arx/brx application:
it works with points so getting started is easy: just get your points into AutoCAD! The points can be layered anyway you choose, and obviously, they need to be congruent in terms of height consistency ( in other words they have to be organised such that the Z values are correct!)
Once we are happy all the points are in the current view in WCS the 1st TheoContour command is : theocollate which loads up the points and reports on the surface they describe ready for the next step:
I kid you not, the arx processes this stuff pretty quickly 2,703 points in about 3 s!
Note that the command line report relays the settings we are using on this model. They can be changed easily; I’m not happy with contours at 4 to the metre indexed on the metre so I go to settings and switch the index interval to 5: 
I’m now ready to contour: 
The command is, you guessed it: theoContour! Plotting the contours takes a little time, this example takes about 45s to generate. Some models can take a while, it’s all dependent on how fine the contours are combined the entity type being generated (lines, polylines or splined polylines).
Not bad for a 1st pass, I would return to the settings and look at smoothing but this gives you a good idea of how simple the process is: and it’s flexible- in effect the datum is the zero value for Z in the current UCS so you can use theocontour to generate contoured surfaces indexed to any plane defined by a UCS! The contours are 2D ploylines in 3D space so they can be edited easily using PEDIT to get them tidy!
So just using 2 commands and tweaking the settings I have got working contours in minutes.
TheoContour also generates profiles and shaded surfaces, the text annotation is pretty neat too but for now I just want to show how simple contouring CAN be if you use TheoContour!
TheoContour can be downloaded as part of TheoLt core at:…