how to calculate cost when sending NFT + datum

[reitcircles]

min_val = min_lovelace( chain_context, output=TransactionOutput(address, Value(0, my_nft)) )

How do i calculate the cost when a datum is associated with the nft (basically sending it to a Smart contract address) using the min_lovelace function ?

[nielstron]

Did you try adding the datum parameter to the TransactionOutput?

I guess you are talking about minUtxo and not transaction fee (the latter is automatically calculated when building a transaction in the transaction builder)

[reitcircles]

yes. i tried datum=true, but it did not change the output. FInally i just calculated the number from the chain params. That worked.

[nielstron]

The datum parameter needs to be set to the actual datum that you attach, not true. Basically you pass the entire transactionoutput the way you would submit it on-chain into the function and then just have to adjust the Lovelace amount in the output.