Surface creation in TBC is definitely one of the software gems. TBC offers a lot of flexibility with appearance and creation of your surfaces. This week’s tip helps understand some of the controls you have over how your breaklines are triangulated. Here is how you might resolve the number of nodes/chords along the surface breaklines.
In Project Settings > Computations > Surface > Breakline Approximation Parameters there is a setting for Hz and Vt tolerance.
![](https://higherlogicdownload.s3.amazonaws.com/TRIMBLE/JiveInlineImages/134094.png)
Here is a surface created using our Processing Feature Code Tutorial.
![](https://higherlogicdownload.s3.amazonaws.com/TRIMBLE/JiveInlineImages/134095.png)
Now, let’s change the project settings and put e.g. 10m for the Hz tolerance.
![](https://higherlogicdownload.s3.amazonaws.com/TRIMBLE/JiveInlineImages/134096.png)
And the result is a less sampled breakline with fewer nodes/triangles along the breakline.
![](https://higherlogicdownload.s3.amazonaws.com/TRIMBLE/JiveInlineImages/134097.png)
Internally, what is happening is that there is a concept of mid-ordinate point to compute the distance of the node between the chord and the arc along the curve as illustrated by the graphics below.
![](https://higherlogicdownload.s3.amazonaws.com/TRIMBLE/JiveInlineImages/134098.png)
![](https://higherlogicdownload.s3.amazonaws.com/TRIMBLE/JiveInlineImages/134099.png)
We hope you find this tip useful regardless if you are going to be exporting surface or breaklines to other products doing contouring for your base map creation within TBC.