Does it fail when the ship cannot succeed in the first chosen direction, or does it get the chance to try rolling in the opposite before failing?

CHoose a direction. If you can fit in any of the three positions (front, aligned with the mark, back), you have to choose one, and it succeeds. If none of the positions fit, it fails. You cannot change direction (or template, for Vipers).

That’s how I read it. There was an argument last night. He was citing how you must Lock something if able before it fails.

1 minute ago, Ravenhull said:

That’s how I read it. There was an argument last night. He was citing how you must Lock something if able before it fails.

Well that's both irrelevant and correct. Locking if able is equivalent to choosing one of the three positions if able.

Well, you know some will grasp at any straw available.

that said, he was right to question how I was using BB-8 last night. Was using it when I was stressed. Will have to apologize about that one. Lost anyway.

I had a dispute come up last night.

Can you complete a barrel roll if the template itself overlaps an asteroid, even though one of the three possible locations on the template is available? Let's say that the template touches in the back, bu if you move the ship all the way forward the ship is clear of the asteroid?

On 1/5/2019 at 10:01 AM, Ravenhull said:

Well, you know some will grasp at any straw available.

that said, he was right to question how I was using BB-8 last night. Was using it when I was stressed. Will have to apologize about that one. Lost anyway.

Next time, just bring Primed Thrusters.

1 hour ago, player655164 said:

I had a dispute come up last night.

Can you complete a barrel roll if the template itself overlaps an asteroid, even though one of the three possible locations on the template is available? Let's say that the template touches in the back, bu if you move the ship all the way forward the ship is clear of the asteroid?

The template itself cannot overlap an obstacle (unless you have a specific ability that allows it). If you can place the template and the ship final position so it doesn't overlap, then that is a valid position.

Rules Reference pg 6

Quote

While attempting to place a ship to complete a barrel roll, the barrel roll can fail if any of the following occurs:

◊ All three positions would cause the ship to overlap or move through an obstacle

The player cannot choose to fail a barrel roll if one of the three positions would not cause the action to fail.

1 hour ago, player655164 said:

Can you complete a barrel roll if the template itself overlaps an asteroid, even though one of the three possible locations on the template is available? Let's say that the template touches in the back, bu if you move the ship all the way forward the ship is clear of the asteroid?

Normally, no. The process of a boost or barrel roll requires that you neither move through (template) nor overlap (final base position) an obstacle.

That said, there are some card abilities that would allow you to go through obstacles, like Collision Detector, Backwards Tailslide, Dash Rendar, and Qi'Ra .