Maya - Reset lattice tweaks on selected lattice points by a percentage (quick 'n' dirty script)

maya_reset_lattice_tweaks_by_percentage.py

import itertools
import maya.api.OpenMaya as om
from maya import cmds


def grouper(iterable, n, fillvalue=None):
    """Collect data into fixed-length chunks or blocks

    Examples:
        grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx

    """

    args = [iter(iterable)] * n
    return itertools.izip_longest(fillvalue=fillvalue, *args)


def reset_lattice_tweaks(points, percent):

    points = [pt for pt in points if cmds.nodeType(pt) == "lattice"]
    points = cmds.ls(points, flatten=True)
    if not points:
        raise RuntimeError("No valid lattice points passed.")
    
    lattices = list(set(cmds.ls(points, objectsOnly=True, type="lattice")))
    points = set(points)
    
    # Store all points of the lattices
    pts_current = {}
    pts_original = {}
    for lattice in lattices:
        all_points = cmds.ls(lattice + ".pt[*][*][*]", flatten=True)
        
        # Current points
        positions = cmds.xform(all_points, query=True, objectSpace=True, t=True)
        positions = list(grouper(positions, 3))
        for pt, pos in zip(all_points, positions):
            pts_current[pt] = pos
            
        # Remove all lattice tweaks
        cmds.lattice(lattice, edit=True, removeTweaks=True)
        
        # Non-deformed points
        positions = cmds.xform(all_points, query=True, objectSpace=True, t=True)
        positions = list(grouper(positions, 3))
        for pt, pos in zip(all_points, positions):
            pts_original[pt] = pos
        
        # Perform blend and restore positions
        for pt in all_points:
            if pt in points:
                # Reset by percentage
                current = om.MVector(pts_current[pt])
                original = om.MVector(pts_original[pt])
                
                diff = original - current
                current += diff * percent 
                
                current = list(current)
                cmds.xform(pt, objectSpace=True, t=current)
                
            else:
                # Keep position before reset tweak
                cmds.xform(pt, objectSpace=True, t=pts_current[pt])

  
sel = cmds.ls(selection=True)
reset_lattice_tweaks(sel, percent=0.5)