Convoke

[LinkToThePast]

ok I have {Chief Engineer} on the battlefield with some other artifact creatures. I tap 5 of my creatures to play {Myr Turbine}. My judge said I can't do that I can only Convoke creature costs. Is this true or is he full of bull honkey

[rarehuntertay]

He was incorrect.
Example:  {Stoke the Flames}

[Pi]

So long as the spell has convoke, you can tap creatures to reduce the casting cost.
Another interesting thing about convoke, you can tap creatures with summoning sickness, because it only says "tap" without using the tap symbol.

[Dsx Cherno]

{sprout swarm}. You can even convoke the buyback.

[LinkToThePast]

Ok so since all artifacts have Convoke I can use my creatures to play {Darksteel Forge}

[redwolv]

Ok so since all artifacts have Convoke I can use my creatures to play {Darksteel Forge}

Correct