117 lines
5.2 KiB
Python
117 lines
5.2 KiB
Python
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"""
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Maya script for removing faces from 3D garement model that are not visible from the outside cameras
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The goal is to imitate scanning artifacts that result in missing geometry
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* Maya 2022+
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"""
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from maya import OpenMaya
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from maya import cmds
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import numpy as np
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from datetime import datetime
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# My modules
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from pygarment.mayaqltools import utils
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def _sample_on_sphere(rad):
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"""Uniformly sample a point on a sphere with radious rad. Return as Maya-compatible floating-point vector"""
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# Using method of (Muller 1959, Marsaglia 1972)
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# see the last one here https://mathworld.wolfram.com/SpherePointPicking.html
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uni_array = np.random.normal(size=3)
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uni_array = uni_array / np.linalg.norm(uni_array) * rad
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return OpenMaya.MFloatVector(uni_array[0], uni_array[1], uni_array[2])
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def _camera_surface(target, obstacles=[], vertical_scaling_factor=1.5, ground_scaling_factor=1.2):
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"""Generate a (3D scanning) camera surface around provided scene"""
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# basically, draw a bounding box around the target
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bbox = np.array(cmds.exactWorldBoundingBox(obstacles + [target])) # [xmin, ymin, zmin, xmax, ymax, zmax]
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top = bbox[3:]
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bottom = bbox[:3]
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center = (top + bottom) / 2
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dims = top - bottom
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dims = [max(dims[0], dims[2]) * ground_scaling_factor, dims[1] * vertical_scaling_factor]
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cube = cmds.polyCube(height=dims[1], depth=dims[0], width=dims[0], name='camera_surface')
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# align with center
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cmds.move(center[0], center[1], center[2], cube, absolute=True)
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# remove bottom face -- as if no cameras there
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# adding '.f[1]' would also remove the ceiling
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cmds.polyDelFacet( cube[0] + '.f[3]') # we know exact structure of default polyCube in Maya2018 & Maya2020
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return cube[0], np.max(dims)
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def remove_invisible(target, obstacles=[], num_rays=30, visibile_rays=4):
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"""Update target 3D mesh: remove faces that are not visible from camera_surface
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* due to self-occlusion or occlusion by an obstacle
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* Camera surface is generated aroung the target as a small "room" with empty floor and ceiling
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In my context, target is usually a garment mesh, and obstacle is a body surface
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Noise control:
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* num_rays -- number of random rays to emit from each face -- the less rays, the more noisy the output is
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* visibile_rays -- number of rays to hit camera surface without obstacles to consider the face to be visible
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BUT at least one ray is always required to consider face as visible!
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"""
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# Follows the idea of self_intersect_3D() checks used in simulation pipeline
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print('Performing scanning imitation on {} with obstacles {}'.format(target, obstacles))
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# generate apropriate camera surface
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camera_surface_obj, ray_dist = _camera_surface(target, obstacles)
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start_time = datetime.now()
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# get mesh objects as OpenMaya object
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target_mesh, target_dag = utils.get_mesh_dag(target)
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camera_surface_mesh, _ = utils.get_mesh_dag(camera_surface_obj)
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obstacles_meshes = [utils.get_mesh_dag(name)[0] for name in obstacles]
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# search for intersections
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target_accelerator = target_mesh.autoUniformGridParams()
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cam_surface_accelerator = camera_surface_mesh.autoUniformGridParams()
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obstacles_accs = [mesh.autoUniformGridParams() for mesh in obstacles_meshes]
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to_delete = []
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target_face_iterator = OpenMaya.MItMeshPolygon(target_dag)
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while not target_face_iterator.isDone(): # https://stackoverflow.com/questions/40422082/how-to-find-face-neighbours-in-maya
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# midpoint of the current face -- start of all the rays
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face_mean = OpenMaya.MFloatPoint(target_face_iterator.center(OpenMaya.MSpace.kWorld))
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face_id = target_face_iterator.index()
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visible_count = 0
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visible = False
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# Send rays in all directions from the currect vertex
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for _ in range(num_rays):
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rayDir = _sample_on_sphere(ray_dist)
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# Case when face is visible from camera surface
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if (utils.test_ray_intersect(camera_surface_mesh, face_mean, rayDir, cam_surface_accelerator) # intesection with camera surface
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and not any([utils.test_ray_intersect(mesh, face_mean, rayDir, acc,) for mesh, acc in zip(obstacles_meshes, obstacles_accs)]) # intesects any of the obstacles
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and not utils.test_ray_intersect(target_mesh, face_mean, rayDir, target_accelerator, hit_tol=1e-5)): # intersects itself
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visible_count += 1
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if visible_count >= visibile_rays: # enough rays are visible -- no need to test more
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visible = True
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if not visible:
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to_delete.append(face_id)
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target_face_iterator.next() # iterate!
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cmds.delete(camera_surface_obj) # clean-up the scene
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# Remove invisible faces
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delete_strs = [target + '.f[{}]'.format(face_id) for face_id in to_delete]
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if len(delete_strs) > 0:
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cmds.polyDelFacet(tuple(delete_strs)) # as this is the last command to execute, it could be undone with Ctrl-Z once
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passed = datetime.now() - start_time
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print('{}::Removed {} faces after {}. Press Ctrl-Z to undo the changes'.format(target, len(to_delete), passed))
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return len(to_delete), passed.total_seconds()
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