most isometric collisions can be done with simple AABB checks
#help on 3D collision with cardboard
pliant summit
AABB = "axis-aligned bounding box"
this means defining little cuboids that collide with each other
you'll be doing this purely using maths
no GM collision functions (probably)
stray thicket
depending on your up vector u might also be able to get away with just using place_meeting as gml mom&dad intended
pliant summit
Cardboard defaults to XY plane with Z up
... is it -Z up or +Z up ...
no idea, can't remember
anyway XY plane collisions 👍
stray thicket
yeah a z up of any sign makes it a lot easier to do place_meeting for a majority of checks. before i locked my game to a rigid, tile-based movement system i pretty much did a instance_place check for all collisions with an additional check for a z-box overlap
spark jetty
split the difference
-Z up on monday wednesday friday, +Z up on sunday tuesday thursday, and spin a roulette wheel for a random axis on saturday
stray thicket
i like it
xfrom, yfrom, zfrom, xto, yto, zto, choose(-1, 0, 1), choose(-1, 0, 1), choose(-1, 0, -1)
spark jetty
better yet