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Second Life Creation

llSetAlpha

void llSetAlpha(float Opacity, integer Face)

Sets the alpha (opacity) of Face.

Sets the alpha (opacity) value for Face. If Face is ALL_SIDES, sets the alpha for all faces. The alpha value is interpreted as an opacity percentage (1.0 is fully opaque, and 0.2 is mostly transparent). This function will clamp alpha values less than 0.1 to 0.1 and greater than 1.0 to 1.

Parameters
Opacity (float)
Face (integer)
Technical Details
  • Return Type: void
  • Energy: 10

In practical terms, “alpha” means “transparency” or “visibility”.

To be clear, llSetAlpha will only affect the prim that the script is in. It will not affect any linked prims. To set the alpha state for those, use llSetLinkAlpha.

Caveats

Section titled “Caveats”
  • llSetAlpha will have no visible effect on faces with a PBR material. To work on faces both with and without a PBR material, use one of these snippets:

Making Objects Invisible

Section titled “Making Objects Invisible”
llSetAlpha(0.0, ALL_SIDES);
llSetLinkPrimitiveParamsFast(LINK_THIS, [PRIM_GLTF_BASE_COLOR, ALL_SIDES, "", "", "", "", "", 0.0, PRIM_GLTF_ALPHA_MODE_MASK, 1.0, ""]);

Making Objects Visible

Section titled “Making Objects Visible”
llSetAlpha(1.0, ALL_SIDES);
llSetLinkPrimitiveParamsFast(LINK_THIS, [PRIM_GLTF_BASE_COLOR, ALL_SIDES, "", "", "", "", "", "", "", "", ""]);

Examples

Section titled “Examples”
float cloakSpeed = 0.1;


default
{
    touch_end(integer total_number)
    {
        float alpha = 1.0;
        while(alpha > 0.0)
        {
            alpha -= 0.1;
            llSetAlpha(alpha, ALL_SIDES);
            llSleep(cloakSpeed);
        }
        state cloaked;
    }
}


state cloaked
{
    touch_end(integer total_number)
    {
        float alpha;
        while (alpha < 1.0)
        {
            alpha += 0.1;
            llSetAlpha(alpha, ALL_SIDES);
            llSleep(cloakSpeed);
        }
        state default;
    }
}

This example demonstrates a cloaking effect that gradually fades an object in and out when touched.

See Also

Section titled “See Also”