how to determine who is in the radius of a spell or not

[clockworkjoe]

Quick question: How do I determine who is affected by a spell with a 10 or 20 foot radius on a standard d20 grid map?

 

[kreynolds]

Draw a circle from the caster's square. Any square that is at least half covered by the circle is affected. A square with a small part of the corner is not affected. That's the easy way for me.

 

[Crothian]

50% of greater filling of square is what we use. That is one of the advantages of hexes, but I only have square maps, so I do it that way.