Houdini Tips – Notes – Teoti Graphix, LLC – 3D

```
// Grow Hairs
```
```
vector dir = { 0, 1, 0 };
```

// dir = @N;    // grow in normal direction

```
float len = 1.0;
```
```
int   steps = 10;
```
```
float jitter = 0.1;
```
```
float seed = 0.12345;
```
```
 
```
```
vector  pos = @P;
```

int             pr = addprim(geoself(), "polyline");

```
 
```
```
// Start the curve with our point
```
```
addvertex(geoself(), pr, @ptnum);
```
```
for (int i = 0; i < steps; i++)
```
```
{
```
```
    pos += dir * len / steps;
```

    pos += (vector(rand( @ptnum + seed )) - 0.5) * jitter;

```
 
```

    // Clone our point to copy attributes

    int pt = addpoint(geoself(), @ptnum);

```
    // But write a new position
```

    setpointattrib(geoself(), "P", pt, pos);

```
 
```

    // Connect the new point to our curve.

```
    addvertex(geoself(), pr, pt);
```
```
    seed += $PI;
```
```
}
```