Applying Quaternion to Vector

I have a Quaternion that, if applied to a Transform, will return the Vector i want when i call transform.up, something like

mBulletSpawnPos.rotation = direction;
mineTarget = mBulletSpawnPos.position + (mBulletSpawnPos.up * distance);

but i have child objects inside mBulletSpawnPos so i need to apply the direction into something else, and i’m lost as to how to get that going.

essentially i need a vector that points towards the mBulletSpawnPos’s up direction with direction applied.

any help is appreciated.

Ok if i understand well, you want to get the ‘up’ vector of ‘mBulletSpawnPos’ apply the Quaternion ‘direction’ to it without modifying the tranform because it has children. Am i right ?

If that so you can do something like that :

mineTarget = mBulletSpawnPos.position + ((direction * mBulletSpawnPos.up) * distance);

Because you can multiply a Quaternion to a vector to apply the quaternion’s rotation to that vector.

Hope that helps you.