TBC Surface Triangle Density Settings

Using TBC Project Settings to create more triangles or densify a surface. -Kyle Easton-

Sitech Northeast
10 steps
5 minutes

TrimbleBusinessCenter

Windows Explorer

Trimble

Here we have a Surface where the triangles need to be densified. The size of each triangle makes the overall surface too "blocky". A machine may not perform at optimum grading accuracy due to the lack of triangles it is crossing as it moves (especially around curves/radius). We will now edit some Project Settings & computation methods in order to Densify this Surface

If we zoom into one of the individual triangles on the surface and use the **Measure** tool on Quick Access Toolbar - we can see the distance between the Triangle Breaks along the edge of the driveway is approximately 10ft (9.46ft). Now - Lets check to verify our Breakline Sampling Distance in the Project Settings.

Click **Project Settings** on the Quick Access Toolbar

***WORLD DOMINATION TIP:*** This Project Settings can also be found on the Home Tab & in a few other ways. Ex: Click on the 'US Survey Feet' text listed on the bottom bar, this will open Project Settings - but directly to the Units & Distances section. Many commands in TBC will have direct ties or links back into these Project Settings.

Click **Computations** in the Project Settings. ***Note - This Computations sub-section is where the User can force TBC into min/max ranges, display settings, rounding rules, or assumptions being made in its arithmetic.***

- ***WORLD DOMINATION TIP: Regardless of your workflow or task in TBC, you should become familiar with the Computation Settings in that topic. These give the USER ultimate control of the data.[CLICK HERE FOR SOME MORE INFO!](https://community.trimble.com/blogs/anna-zapel/2025/02/18/tbc-tip-236-editing-surfaces-adjust-flat-triangles)***

Click **Surface** sub-grouping under Computations.

Under the Breakline Approximation Settings - **Maximum Sampling Distance** line we see the current setting is 10ft.

NOTE - STEP 2 ABOVE - This confirms our Measure Tool distance of 9.46ft which proves the 10ft Breakline Sampling Distance setting is being utilized in the surface build computations. At no point will this Measured distance exceed the Value placed in the "Maximum Sampling Distance" [STEP_2_HERE](https://scribehow.com/viewer/Change_Surface_Computation_Settings_in_Project_Settings__eXxKB73tSp-_NrjKqT9qeg?scrollToActionId=b4751902)

Change the **Maximum Sampling Distance** to 5 (5ft).

*Note* - In theory once this 5ft distance is applied, the software should take the original 10ft sample distance and cut it in half. This will result in an approximate DOUBLING of the number of Triangles (vertices) along the Breaklines.

Click **OK** to Apply the settings changes.

Click **Measure Tool** on the Quick Access Toolbar - measure the distance of the triangle break distances along the Breakline. This should be approx. 5ft (but always less) to reflect the changed sampling distance in Project Settings.

***WORLD DOMINATION TIP: There is no 'correct' answer in the Surface Modeling world to the question*** "What should my breakline sampling distance be set to?" ***Factors such as job specifications for accuracy, types of work being completed, or possibly even the attachment on an automated machine may influence the final value of this distance. A good rule of thumb I usually use as a starting point: Site Work = 5-10ft, Corridor/Road Work = 2.5-5ft.***

In the image below I have turned the sampling distance all the way down to 1.00ft. What Sampling Distance would you choose for this small Drive-Thru restaurant site?

***WORLD DOMINATION TIP: I personally would use a 5ft distance for this job. I think it creates enough extra triangles where you are not having the blade "clunk" when moving between them, but also covers the radius curves enough to allow machine to grade smoothly.*** MODELING IS ART, DONT FORGET IT :-) \-Kyle Easton-