Redeeming

Redemption destroys a Shape and pays exactly its backing. There is no partial redemption and no way to add ETH to an existing Shape.

function redeem(uint256 tokenId) external;
function redeemTo(uint256 tokenId, address payable recipient) external;
function redeemBatch(uint256[] calldata tokenIds) external returns (uint256 totalWei);
function redeemBatchTo(uint256[] calldata tokenIds, address payable recipient) external returns (uint256 totalWei);
function burn(uint256 tokenId) external;   // IERC721Value (draft ERC-8060)

Rules

• Owner only. msg.sender must be ownerOf(tokenId), else NotShapeOwner(tokenId, caller). An approved operator cannot redeem; it must transfer the token to itself first.
• Payout. redeem and burn pay the caller. redeemTo and redeemBatchTo pay recipient, which cannot be zero (InvalidRecipient). A batch makes a single transfer of the total after burning every token.
• Black Shapes. redeem* reverts TokenIsBlack for a Black Shape. burn accepts one and destroys it with no ETH call. For a normal Shape burn and redeem are identical.
• Failure. If the ETH transfer fails the whole call reverts EthTransferFailed(to, amountWei). The tokens survive. The payout is a plain call with all remaining gas, so a contract recipient may run logic in receive, under the reentrancy guard.
• Batches. An empty array reverts ZeroQuantity. A repeated id reverts the second time, because the token no longer exists.
• Owner token. Redeeming or burning the owner token ends collection ownership permanently: owner() returns zero, ownerToken() reverts NoOwnerToken, and OwnerTokenMoved(tokenId, type(uint256).max) is emitted.

Accounting

Each redemption lowers totalSupply by one and redeemableBacking by the payout, before the ETH leaves. The token's state, stored modules and any inert compose records it left behind are cleared or unreachable; its id is never reissued. The ETH is sent last, under the reentrancy guard.

Events

originCount on ShapeRedeemed lets an event-only indexer track the global origin balance without a pre-burn read.

Reading the payout first

valueOf(tokenId) and backingOf(tokenId) return the exact wei redeem will pay. Both revert for a token that does not exist and return zero for a Black Shape. exists(tokenId) never reverts.