setpointattrib Example (VEX)

What it does

Creates a new point and writes an attribute value onto it by point number. Where @Cd = ... edits the current element, setpointattrib lets you write to any point you name - including one you just added.

When to use it

Use it whenever you generate geometry in a wrangle and need to set attributes on the new elements: scattering points, building curves, or emitting from a detail wrangle where there is no current point to bind.

The VEX code

int pt = addpoint(0, set(0, 0, 0));
// addpoint returns the new point number; pass it to setpointattrib.
// The final arg is the write mode ("set", "add", "max", and so on).
setpointattrib(0, "Cd", pt, {1, 0, 0}, "set");

Inputs and assumptions

• Input 0 is the geometry you are writing to (the wrangle edits input 0 by default).
• addpoint returns the new point number, which you pass to setpointattrib.
• Often run in a detail (or points) wrangle when generating geometry.

Common mistakes

• Using @Cd instead of setpointattrib when the point is not the current element - @ only writes the element the wrangle is on.
• Wrong value type: Cd is a vector, so pass {1, 0, 0}, not a single float.
• Forgetting the mode argument ("set", "add", "max", and so on) or misspelling it.
• Expecting the attribute to exist for later nodes - creating it here is fine, but downstream nodes must reference the same name.

Frequently asked questions

What is the difference between @Cd and setpointattrib?

@Cd writes to the current element the wrangle is running on; setpointattrib writes to any point by number, including points you create with addpoint.

Which wrangle should I use setpointattrib in?

Any, but it is most common in a detail or points wrangle when you are generating geometry and setting attributes on new points.

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