cast range - object editor range vs actual max range

[Cheshire]

I created a spell based on channel. I set the cast range to 800.

I noticed that my unit will cast the spell even when the range is greater than 800, from a little testing it seems like the max I can cast is till > 865.
whereas, when I cast out from further of range the unit will walk towards the target untill it is in 800 range and then cast.

I know this mechanic is pretty well known around the blink ability (specifically around blink daggr in dota), but I wasn't aware that there was a default cast range vs max cast range thing going on with all spells.

is there any way to access the accurate number of "max cast range"? is it changeable?

 

[Uncle]

I created a spell based on channel. I set the cast range to 800.

I noticed that my unit will cast the spell even when the range is greater than 800, from a little testing it seems like the max I can cast is till > 865.
whereas, when I cast out from further of range the unit will walk towards the target untill it is in 800 range and then cast.

I know this mechanic is pretty well known around the blink ability (specifically around blink daggr in dota), but I wasn't aware that there was a default cast range vs max cast range thing going on with all spells.

is there any way to access the accurate number of "max cast range"? is it changeable?

I imagine it's tied to collision size. The number you may have seen was 864 (max cast range + 32 col size of caster + 32 col size of target) but I could be wrong about that. There's also Range Motion Buffer in the Gameplay Constants which I THINK applies here but maybe not. That would allow casts which have "begun casting" to continue doing so as long as the target stays within (Max Cast Range + 250.00) range.

 

[Nichilus]

Yes, collision size plays role in cast range. Use this function Doc - IsUnitInRange to check if unit is within cast range, as that automatically includes their collision sizes.