what can i legally pre measure?

By DarkGuard, in X-Wing Rules Questions

if i move and when i am deciding my action can i remeasure the distance between me and a enemy and then make my choice of action?

No, you may not.

Unless you need to know the distance to something, because of an effect, or because you're shooting at the thing, you can't measure distances.

According to the core rulebook, you measure when you are shooting, or when you are trying to target lock something. In both cases you can measure to any number of ships, before committing to a target.

The tournament rules tighten this up slightly

Measuring Range
Players may only measure range and/or use the range ruler to determine
whether a ship is inside or outside of a firing arc at the following times:
• When a ship becomes the active ship during the combat phase, the active
player can measure range from the active ship to any enemy ships before
declaring one as its target.
• When a player declares a ship’s ability that requires another ship (or ships)
to be at a certain range, the player trying to resolve the ability can measure
range from their ship to any valid ships before resolving the ability.
• After declaring the intended target of a target lock action, the active player
may measure range to the intended target, and only to the intended target.
It's probably a good idea, to confirm with your opponent before you start your game, whether or not you play by the tournament rules, or the standard rules. There are other differences in the two rulesets than I mentioned.
But none of the rulesets allow you to measure distance to an enemy ship before deciding to boost or barrel roll or something like that.
You can download the rulesets, FAQ and other stuff from here: http://www.fantasyflightgames.com/edge_minisite_sec.asp?eidm=174&esem=4

thanks heaps =D

thinking of using tactician more and was wondering if i could check to see if it would be in range 2 if not barrel roll forward or back. but you answered that thanks =D

If you want to use Tactician, or any of the range dependent upgrades, you've got to learn to estimate ranges accurately. It's a skill that comes with practice. Lots of practice.

So considering a boost action cannot be taken if it would bump into a ship, how do you know when you can boost?

you declare the action & direction, if it is possible you MUST perform it, if it is not possible you may then choose a different direction for the boost or choose another action

K.Thanks.

you declare the action & direction, if it is possible you MUST perform it

This is only half right. This is true for Competitive Rules, and is also true for barrel roles and decloaks as well.

But under standard rules you can check for boost, barrel rolls and decloaks before you commit to the action.

Quite correct Vanor. Not everyone plays to the competitive rules.