Utility_Apps/Blender/simple scripts/CSV Terrain Import for Blender/readme.md

# CSV Terrain Import for Blender

This workflow imports survey-style CSV point data into Blender as:

1.  **Empties** (named from the `label` column)
    
2.  A **triangulated 3D mesh surface** generated from those empties
    

It handles:

*   Large world coordinates (offsets near origin)
    
*   Mirrored Y axis correction
    
*   Z normalization (lowest point = 0)
    
*   Unit conversion (CSV in feet → Blender scene units)
    

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# Requirements

*   Blender 4.x
    
*   SciPy installed in Blender’s Python (for Delaunay triangulation)
    

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# Installing SciPy in Blender



# ✅ Correct Way to Install SciPy for Blender 4.5

You must use **Blender’s Python executable**, not your system one.

Open PowerShell or CMD and run:

Code

`"C:\\Program Files\\Blender Foundation\\Blender 4.5\\4.5\\python\\bin\\python.exe" -m ensurepip`

Then:

Code

`"C:\\Program Files\\Blender Foundation\\Blender 4.5\\4.5\\python\\bin\\python.exe" -m pip install --upgrade pip`

Then:

Code

`"C:\\Program Files\\Blender Foundation\\Blender 4.5\\4.5\\python\\bin\\python.exe" -m pip install scipy`

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# CSV Format

Your CSV must include the following headers:

Code

id,x,y,z,label

Example:

Code

1,436942.2079,856128.116,869.0791,3/4"RBR  
2,436943.0254,856128.0656,868.833,BT

Assumptions:

*   Coordinates are in **feet**
    
*   X/Y are projected coordinates
    
*   Z is elevation
    
*   `label` will become the Empty name
    

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# Step 1 — Import CSV as Empties

Open Blender:

1.  Go to **Scripting workspace**
    
2.  Create a new script
    
3.  Paste the “Script 1” code
    
4.  Set your `csv_path`
    
5.  Run the script
    

What this does:

*   Creates a collection named `CSV_Points`
    
*   Creates one Empty per CSV row
    
*   Offsets X/Y near origin
    
*   Flips Y axis to match Blender
    
*   Sets lowest Z to 0
    
*   Converts feet → Blender units automatically
    

You should now see labeled empties in 3D space.

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# Step 2 — Generate Triangulated Mesh

1.  Create a new script
    
2.  Paste the “Script 2” code
    
3.  Run it
    

What this does:

*   Reads all empties in `CSV_Points`
    
*   Performs Delaunay triangulation (XY plane)
    
*   Builds a 3D triangulated mesh using the empty Z values
    
*   Creates a new object named `TriangulatedMesh`
    

You now have a terrain surface mesh.


Here’s a short section you can add to your `README.md` explaining the filtering behavior.

You can paste this anywhere after the “Generate Triangulated Mesh” step.

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## Skipping Certain Survey Points

The triangulation script supports excluding specific points based on the **name of the Empty** (which comes from the CSV `label` column).

This is useful because survey datasets often contain points that should **not** be part of a terrain surface, for example:

*   House corners
    
*   Utilities
    
*   Reference marks
    
*   Temporary layout points
    

The script ignores any Empty whose name contains certain keywords.

Current defaults:


`HSE` 
`FOO` 
`BAR`

The filtering is **case-insensitive**.  
Examples that will be skipped:


```
HSE  
hse\_corner  
foo\_marker  
BAR-TEST  
my\_house\_hse\_point
```
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### How It Works

Before triangulation, the script checks each Empty in the `CSV_Points` collection and removes any that match an exclusion keyword. Only the remaining points are used to build the terrain mesh.



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### Customizing the Filter

You can edit the list inside Script 2:

`EXCLUDE_KEYWORDS = ["HSE", "FOO", "BAR"]`


### Why This Matters

Triangulation assumes every point belongs to the same continuous surface.  
If non-terrain points are included (tops of foundations, utility lids, walls, etc.), the mesh will produce long spikes, inverted triangles, or unrealistic slopes.

Filtering produces a much cleaner and more accurate terrain model.

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# Unit Handling

This workflow assumes:

*   CSV coordinates are in **feet**
    
*   Blender scene may be meters, feet, etc.
    

The script automatically converts:

Code

CSV feet → meters → Blender units

So your terrain will scale correctly regardless of Blender’s unit settings.

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# Coordinate Adjustments Explained

### Offset to Origin

Large survey coordinates can cause floating-point precision issues.

The script subtracts:

*   Minimum X
    
*   Minimum Y
    
*   Minimum Z
    

So geometry is created close to `(0,0,0)`.

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### Y-Axis Flip

Many survey systems increase Y in the opposite direction from Blender.

The script flips Y so the terrain is not mirrored.

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# Common Issues

## Mesh looks mirrored

Ensure the Y-flip line exists:

Python

y\_adj \= \-(y \- y\_offset) \* scale

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## Mesh scale is wrong

Verify:

*   CSV is truly in feet
    
*   Blender unit system is set correctly
    
*   `CSV_UNIT_TO_METERS = 0.3048`
    

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## SciPy Import Error

If you see:

Code

ModuleNotFoundError: No module named 'scipy'

Reinstall SciPy into Blender’s Python.

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# Recommended Workflow

For large terrain datasets:

1.  Import empties first
    
2.  Inspect distribution visually
    
3.  Then triangulate
    
4.  Optionally delete empties after mesh creation
    

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# Optional Improvements

Possible enhancements:

*   Assign vertex colors based on label
    
*   Assign materials per label
    
*   Automatically delete empties after mesh creation
    
*   Add smoothing or decimation
    
*   Convert to Geometry Nodes workflow