Using the new CalculateDistance tool

A few notes

After some more implementations, this tool is officially ready to use. I added a new “developer” mode, so that it can be used within another script rather than using it as a standalone.

Previously this tool only displayed the current frame distance between the selected objects through a prompt box, and that was it.

In order to make it more useful, I decided to add a few more functions that return the actual value of the distance as a string. This string can then be used within any script.

Usage of the tool

To install, simply download the tool here: CalculateDistance and unzip it to your /maya/scripts/ folder. Inside Maya, in a Script Editor python tab you can type the following commands depending on the mode you want to use. You can map these commands to a hot key or to a shelf button.

Regular Mode

1. Calculate distance from current camera to selected object’s pivot:

import CalculateDistance;CalculateDistance.camToPivot(); 

2. Distance from current camera to closest point in a selected geometry:

import CalculateDistance;CalculateDistance.camToSurface(False);

3. Same usage than previous point, but creating a locator in closest point.

import CalculateDistance;CalculateDistance.camToSurface(True);

4. Distance between 2 selected objects (No camera involved)

import CalculateDistance;CalculateDistance.between2Objects();

Developer mode

This mode returns the distance as a string instead of displaying it. The usage is the same than the regular mode, with these functions available:

import CalculateDistance
CalculateDistance.camToPivotDev()
CalculateDistance.camToSurfaceDev()
CalculateDistance.between2ObjectsDev()

Example
If at some point you want to hook the distance between the camera and an object’s closest vertex to an attribute in a certain frame range, you can do the following:

# Import maya commands library
import maya.cmds as cmds
# Import the tool
import CalculateDistance
# Get the start frame of the current timeline
startFrame = cmds.playbackOptions( q=True,min=True )
# Get the last inclusive frame
endFrame = cmds.playbackOptions( q=True,max=True )+1.0
# Get the current selected item
getSelection=cmds.ls(selection=True)
# Check if there is anything selected.
if getSelection:
    # Iterate through each frame
	for frame in range(int(startFrame), int(endFrame)):
	    # Select the item again in case it gets de-selected during the process
		cmds.select(getSelection)
		# Jump to the current frame
		cmds.currentTime(frame)
		# Calculate the distance and store it in a variable
		distance=CalculateDistance.camToSurfaceDev()
        # Set the focal length of the camera to the distance value		
		cmds.setAttr("perspShape.focalLength", distance)
		# Add a keyframe to "bake" it
		cmds.setKeyframe('perspShape.focalLength')

This snippet will “bake” the distance into the perspective camera’s focalLength attribute. You can use that loop and adapt it to your needs.