It's possible to make a visible object that the UI thinks is a water exclusion surface

[canny]

1. Edit a box and set the Shininess (specular) texture to the Blank texture.

2. Apply the water exclusion surface script.

default
{
    state_entry()
    {
        // Make this prim a water_exclusion_surface.
        llSetPrimitiveParams([PRIM_BUMP_SHINY, ALL_SIDES, PRIM_SHINY_NONE, PRIM_BUMP_NONE,
            PRIM_COLOR, ALL_SIDES, <1.0, 1.0, 1.0>, 1.0, PRIM_TEXGEN, ALL_SIDES, PRIM_TEXGEN_DEFAULT,
            PRIM_TEXTURE, ALL_SIDES, "e97cf410-8e61-7005-ec06-629eba4cd1fb", ZERO_VECTOR, ZERO_VECTOR, 0.0]);
        
        // Delete ourselves from the prim; we are no longer needed.
        llRemoveInventory(llGetScriptName());
    }
}

3. This makes the box black and the Texture tab does not have "Hide water" checked.

4. Edit the box and set the Shininess (specular) texture to the None texture, removing the Blank texture.

Observed: The object is still visible. The UI now shows that "Hide water" is checked.

Expected: I'm not sure. Should this object turn into a water exclusion surface when the Shininess is set to None?

Should the UI detect that this is not a water exclusion surface object and leave the "Hide water" checkbox unchecked?

https://secondlife.canny.io/admin/board/bug-reports/p/its-possible-to-make-a-visible-object-that-the-ui-thinks-is-a-water-exclusion-su

Video: https://github.com/user-attachments/assets/d4a76d0a-d3ac-4a7f-bc56-44f478568f13

[canny]

This issue has been linked to a Canny post: It's possible to make a visible object that the UI thinks is a water exclusion surface 🎉

[maxim-productengine]

After the change, "Hide water" won't be checked after the step 4.
The reason why the object is not really water exclusion surface after the steps in the issue: Alpha mode (Diffuse) is set to 'none', and water exclusion surface requires 'alpha blending'.

[AtlasLinden]

After performing the above steps, the Hide Water option is no longer checked. Alpha mode is also still set to None
This matches what is seen in world which is a black box.
Setting Alpha mode to Alpha blending, while the shininess texture is not applied, automatically checks the Hide Water option and the selected prim faces become water exclusion surfaces.

Passed QA.
Verified on the Second Life Release 7.1.14.14742193597 (2025.04) on Win11/MacOS