llAllowInventoryDrop

void llAllowInventoryDrop(integer Flag)

If Flag == TRUE, users without object modify permissions can still drop inventory items into the object.

Parameters

Flag (integer): Boolean, If TRUE allows anyone to drop inventory on prim, FALSE revokes.

Technical Details

Return Type: void
Energy: 10

To perform the drop operation, drag an item from your inventory and drop it onto the prim while holding down Ctrl. When everything is correct, the prim will be framed in red just before you release it.

Ownership of the dropped inventory item changes to the owner of the prim. Next owner permissions kick in on the item that was dropped. Non-transfer items cannot be dropped into a prim owned by someone else.

Examples

Basic Event Handling - Non-Modifier Drop

When llAllowInventoryDrop is set to TRUE and an item is successfully dropped by someone without modify permissions, the changed event occurs with the CHANGED_ALLOWED_DROP bit set:

changed(integer change)
{
    if (change & CHANGED_ALLOWED_DROP)
        llSay(0, "Your contribution is appreciated, o ye non-permitted modifier!");
}

Basic Event Handling - Modifier Drop

When an item is successfully dropped by someone with modify permissions, the event that occurs is CHANGED_INVENTORY, regardless of the state of llAllowInventoryDrop():

changed(integer change)
{
    if (change & CHANGED_INVENTORY)
        llSay(0, "Your contribution is appreciated, o ye permitted modifier!");
}

Testing for Either Changed Event

To test for either changed event, use bitwise OR:

changed(integer change)
{
    //PUBLIC_CHANNEL has the integer value 0
    if (change & (CHANGED_ALLOWED_DROP | CHANGED_INVENTORY))
        llSay(PUBLIC_CHANNEL, "yeppers, inventory changed somehow.");
}

Toggle Inventory Drop on Touch

This example toggles llAllowInventoryDrop off and on with each touch:

integer allow;

default
{
    touch_start(integer num)
    {
        llAllowInventoryDrop(allow = !allow);
        llOwnerSay("llAllowInventoryDrop == " + llList2String(["FALSE","TRUE"], allow));
    }

    changed(integer change)
    {
        //note that it's & and not &&... it's bitwise!
        if (change & CHANGED_ALLOWED_DROP)
            llOwnerSay("The inventory has changed as a result of a user without mod permissions dropping
                        an item on the prim and it being allowed by the script.");
    }
}

Caveats and Limitations

Link Sets: In a link set, llAllowInventoryDrop must be executed from a script within the root prim or it fails silently.
Scripts Cannot Be Dropped: Scripts are an exception to what is allowed to be dropped in. If a user without modify permissions attempts to drop a script, the inventory addition is rejected and the prim shouts “Not permitted to edit this!” For security reasons, only the owner or those with modify rights can drop scripts.
Locked Objects: Will not work if “Locked” is ticked under the Object tab in the prim properties.
Texture Drop Precision: When dropping a texture, ensure you see a red box framing the target prim and don’t release Ctrl until the texture is actually inside the box. If you see a white frame or release Ctrl too soon, the texture will be applied to the prim face instead of being added to inventory.
No Way to Identify Dropper: There is no built-in way to tell who dropped the item. If you need this information, consider making the user touch the prim first to capture their details from the touch event, then enable llAllowInventoryDrop and capture the drop event.
No Way to Identify What Was Dropped: There is no way based solely on llAllowInventoryDrop to determine what was dropped. See the WhoAddedWhat script pattern for solutions.
Modify Rights Bypass: People with modify rights to your stuff can drop items anyway, even without llAllowInventoryDrop. Similarly, if you own a prim but lack modify rights, you cannot drop anything unless the creator first enabled llAllowInventoryDrop(TRUE).
Irreversible Drop: If you have a prim you don’t have modify rights to, but the creator set llAllowInventoryDrop(TRUE), you can drop stuff in but can never delete it. You can only move it to your inventory.

User Experience Notes

Communication Required: If you want users to drag and drop items, explain the process clearly and emphasize holding down Ctrl.
Motor Skill Requirements: Fine motor skills are needed for this operation. Users with unsteady hands or using trackpads may struggle.
Unintended Drops: When users fill containers via drag and drop, they may accidentally drop items into the wrong prim part (like into a bow instead of the giftbox). Consider offering an alternative: have users right-click the prim, choose “Open”, and drag items into the Object Contents window, which provides a much larger, safer target.

Use Cases

A common application is a public “suggestion box” that allows people to drop notecards without requiring modify permissions.