Help needed for small script

V-Ray V-Ray Common Off-topic
1

Hi,
I’m looking for a simple script for moving one object in z axis controlled by other object. The way I see this would be to get first the z position of the pivot point from the control object via script, and then apply it to the z axis of the one that I want to move.

I know that there are ways, other than scripting, for doing this but those won’t work in the case I have. I must say too, that I have no idea of scripting.

thanks in advance,
Manuel

2

Why not Wire the Params ? Will do the same as scripting it.

As for scripting :

Assign a Float script controller to the Z channel of the child object
In the script controller create a variable and assign it to the parent node
use this variable to access the z possition as follows :
box.pos.z
where “box” is the variable name.

Regards,
Thorsten

3

Thanks Thorsten,

now that you said that wire and scripting is the same maybe I’m going in a wrong direction. I’ll try to explain the case:
I’m trying to get people walking in a scene where the terrain has slopes. So, I have a mesh “people” with point cache that walks straight in the z axis. Then, I have an object, for example a plain, which follows the surface slope using “conform” space warps. I want the object “people” driving the movement of the plain through the surface in xy axes, that’s easy using an “attachment constraint” (the plain get the z position from the conform surface). Ideally, I would like to find a way where the object “people” get back the z axis info from the plain but via wiring is not working. Do all this process has any sense to you?

Thanks again for your help.

Manuel

4

just to get that straight. You got ppl walking and they should stick to a groundplane ? If so i’d suggest using a raycast to directly get the z-height of the plane for the object’s x/y position.

Regards,
Thorsten

5

yeah, you got the idea but I don’t know what you mean by “raycast”

Regards,
Manuel

6

raycasting is a built in function in maxscript. basically it simply casts a ray into the scene looking for a specified object. If the ray intersects that object the function returns the coordinates of the intersection. Quick example :

  • Create a plane
  • Add a noise modifier and raise the z-strength
  • create a dummy above the plane
  • add a FloatScript controller to the dummy’s Z-Coordinate
  • Create a Variable called “floor” and assign it to the plane node
  • Create a Variable called “position” and assign it to the Dummy node itself

Then use the following script :

 P = position.position
local iRay= ray P [0,0,-1]
z = IntersectRay Floor iRay
z.pos.z+50

Short explanation:

P = position.position
Creates a new Variable holding the Dummy’s position (remember, the Variable referring to the Dummy is called “position” hence the weird position.position
local iRay= ray P [0,0,-1]
Creates a local variable called iRay that is a ray (vector) from P (the Dummy’s position) Straight downwards
z = IntersectRay Floor iRay
Intersects the Ray created as iRay with the Floor node and store the result in a variable called z
z.pos.z+50
Return the final result. z.pos.z is the z component of the intersection coordinates. The + 50 is used to offset a dummy upwards. You’ll have to adjust that one to fit your needs. If you move the dummy in the x/y plane now it will automatically adjust its z-position in realtime.

A short warning, this is rather bruteforce and will fail if the dummy is moved outside the plane’s x/y dimensions as there are no errorchecks or anything.

Regards,
Thorsten

7

wow, that’s nice! Looks difficult though; but I will try it.

Many thanks,
Manuel