├── README.md
├── chair_pcl.npy
├── mitsuba_scene.png
└── pointflow_fig_colorful.py


/README.md:
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 1 | # Point Cloud Renderer
 2 | 
 3 | Instructions and scripts for rendering point cloud figures shown in **PointFlow: 3D Point Cloud Generation with Continuous Normalizing Flows**.
 4 | 
 5 | [[Paper]](https://arxiv.org/abs/1906.12320) [[Project GitHub]](https://github.com/stevenygd/PointFlow).
 6 | 
 7 | The script generates a XML file, which describes a 3D scene in the format used by Mitsuba. You will then be able to render it with Mitsuba.
 8 | 
 9 | ## Dependencies
10 | * Python 3.6
11 | * [Mitsuba Renderer](http://www.mitsuba-renderer.org/)
12 | 
13 | ## Instructions
14 | ```bash
15 | # Generate scene XML file
16 | python3.6 pointflow_fig_colorful.py
17 | 
18 | # Render using Mitsuba
19 | mitsuba mitsuba_scene.xml
20 | ```
21 | 
22 | ## Examples
23 | <p float="left">
24 |     <img src="mitsuba_scene.png" height="256"/>
25 | </p>
26 | 
27 | ## Cite
28 | Please consider citing our work if you find it useful:
29 | ```latex
30 | @article{pointflow,
31 |  title={PointFlow: 3D Point Cloud Generation with Continuous Normalizing Flows},
32 |  author={Yang, Guandao and Huang, Xun, and Hao, Zekun and Liu, Ming-Yu and Belongie, Serge and Hariharan, Bharath},
33 |  journal={arXiv},
34 |  year={2019}
35 | }
36 | ```
37 | 


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/chair_pcl.npy:
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https://raw.githubusercontent.com/zekunhao1995/PointFlowRenderer/ed18fc97bebece1beecd1846d1bb8d76911573c0/chair_pcl.npy


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/mitsuba_scene.png:
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https://raw.githubusercontent.com/zekunhao1995/PointFlowRenderer/ed18fc97bebece1beecd1846d1bb8d76911573c0/mitsuba_scene.png


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/pointflow_fig_colorful.py:
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  1 | import numpy as np
  2 | 
  3 | def standardize_bbox(pcl, points_per_object):
  4 |     pt_indices = np.random.choice(pcl.shape[0], points_per_object, replace=False)
  5 |     np.random.shuffle(pt_indices)
  6 |     pcl = pcl[pt_indices] # n by 3
  7 |     mins = np.amin(pcl, axis=0)
  8 |     maxs = np.amax(pcl, axis=0)
  9 |     center = ( mins + maxs ) / 2.
 10 |     scale = np.amax(maxs-mins)
 11 |     print("Center: {}, Scale: {}".format(center, scale))
 12 |     result = ((pcl - center)/scale).astype(np.float32) # [-0.5, 0.5]
 13 |     return result
 14 | 
 15 | xml_head = \
 16 | """
 17 | <scene version="0.6.0">
 18 |     <integrator type="path">
 19 |         <integer name="maxDepth" value="-1"/>
 20 |     </integrator>
 21 |     <sensor type="perspective">
 22 |         <float name="farClip" value="100"/>
 23 |         <float name="nearClip" value="0.1"/>
 24 |         <transform name="toWorld">
 25 |             <lookat origin="3,3,3" target="0,0,0" up="0,0,1"/>
 26 |         </transform>
 27 |         <float name="fov" value="25"/>
 28 |         
 29 |         <sampler type="ldsampler">
 30 |             <integer name="sampleCount" value="256"/>
 31 |         </sampler>
 32 |         <film type="ldrfilm">
 33 |             <integer name="width" value="1600"/>
 34 |             <integer name="height" value="1200"/>
 35 |             <rfilter type="gaussian"/>
 36 |             <boolean name="banner" value="false"/>
 37 |         </film>
 38 |     </sensor>
 39 |     
 40 |     <bsdf type="roughplastic" id="surfaceMaterial">
 41 |         <string name="distribution" value="ggx"/>
 42 |         <float name="alpha" value="0.05"/>
 43 |         <float name="intIOR" value="1.46"/>
 44 |         <rgb name="diffuseReflectance" value="1,1,1"/> <!-- default 0.5 -->
 45 |     </bsdf>
 46 |     
 47 | """
 48 | 
 49 | xml_ball_segment = \
 50 | """
 51 |     <shape type="sphere">
 52 |         <float name="radius" value="0.025"/>
 53 |         <transform name="toWorld">
 54 |             <translate x="{}" y="{}" z="{}"/>
 55 |         </transform>
 56 |         <bsdf type="diffuse">
 57 |             <rgb name="reflectance" value="{},{},{}"/>
 58 |         </bsdf>
 59 |     </shape>
 60 | """
 61 | 
 62 | xml_tail = \
 63 | """
 64 |     <shape type="rectangle">
 65 |         <ref name="bsdf" id="surfaceMaterial"/>
 66 |         <transform name="toWorld">
 67 |             <scale x="10" y="10" z="1"/>
 68 |             <translate x="0" y="0" z="-0.5"/>
 69 |         </transform>
 70 |     </shape>
 71 |     
 72 |     <shape type="rectangle">
 73 |         <transform name="toWorld">
 74 |             <scale x="10" y="10" z="1"/>
 75 |             <lookat origin="-4,4,20" target="0,0,0" up="0,0,1"/>
 76 |         </transform>
 77 |         <emitter type="area">
 78 |             <rgb name="radiance" value="6,6,6"/>
 79 |         </emitter>
 80 |     </shape>
 81 | </scene>
 82 | """
 83 | 
 84 | def colormap(x,y,z):
 85 |     vec = np.array([x,y,z])
 86 |     vec = np.clip(vec, 0.001,1.0)
 87 |     norm = np.sqrt(np.sum(vec**2))
 88 |     vec /= norm
 89 |     return [vec[0], vec[1], vec[2]]
 90 | xml_segments = [xml_head]
 91 | 
 92 | pcl = np.load('chair_pcl.npy')
 93 | pcl = standardize_bbox(pcl, 2048)
 94 | pcl = pcl[:,[2,0,1]]
 95 | pcl[:,0] *= -1
 96 | pcl[:,2] += 0.0125
 97 | 
 98 | for i in range(pcl.shape[0]):
 99 |     color = colormap(pcl[i,0]+0.5,pcl[i,1]+0.5,pcl[i,2]+0.5-0.0125)
100 |     xml_segments.append(xml_ball_segment.format(pcl[i,0],pcl[i,1],pcl[i,2], *color))
101 | xml_segments.append(xml_tail)
102 | 
103 | xml_content = str.join('', xml_segments)
104 | 
105 | with open('mitsuba_scene.xml', 'w') as f:
106 |     f.write(xml_content)
107 | 
108 | 
109 | 


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