Seam when rendering triangle close up

[tobyclh]

If you do not know the root cause of the problem / bug, and wish someone to help you, please post according to this template:

🐛 Bugs / Unexpected behaviors

I am trying to render a simple quad created by two triangles, but there is a seam when rendered from a close distance.

Instructions To Reproduce the Issue:

Please include the following (depending on what the issue is):

1. Any changes you made (git diff) or code you wrote Minimal working example based on the tutorial

import os
import sys
import torch
import pytorch3d
import os
import torch
import matplotlib.pyplot as plt
import math

from pytorch3d.io import load_objs_as_meshes, load_obj

# Data structures and functions for rendering
from pytorch3d.structures import Meshes
from pytorch3d.vis.plotly_vis import AxisArgs, plot_batch_individually, plot_scene
from pytorch3d.vis.texture_vis import texturesuv_image_matplotlib
from pytorch3d.renderer import (
    look_at_view_transform,
    FoVPerspectiveCameras, 
    PointLights, 
    DirectionalLights, 
    Materials, 
    RasterizationSettings, 
    MeshRenderer, 
    MeshRasterizer,  
    SoftPhongShader,
    TexturesUV,
    TexturesVertex
)

# add path for demo utils functions 
import sys
import os
sys.path.append(os.path.abspath(''))

# Setup
if torch.cuda.is_available():
    device = torch.device("cuda:0")
    torch.cuda.set_device(device)
else:
    device = torch.device("cpu")

obj_filename = 'plane.obj'


mesh = load_objs_as_meshes([obj_filename], device=device)
fov = 45
half_fov_rad = (fov / 2) / 180.0 * math.pi
height = 0.5 / math.tan(half_fov_rad)
R, T = look_at_view_transform(height, 0, 0) 
cameras = FoVPerspectiveCameras(device=device, R=R, T=T, fov=fov)

raster_settings = RasterizationSettings(
    image_size=512, 
    blur_radius=0.0, 
    faces_per_pixel=1, 
)

# Place a point light in front of the object. As mentioned above, the front of the cow is facing the 
# -z direction. 
lights = PointLights(device=device, location=[[0.0, 0.0, 1.0]])

# Create a Phong renderer by composing a rasterizer and a shader. The textured Phong shader will 
# interpolate the texture uv coordinates for each vertex, sample from a texture image and 
# apply the Phong lighting model
renderer = MeshRenderer(
    rasterizer=MeshRasterizer(
        cameras=cameras, 
        raster_settings=raster_settings
    ),
    shader=SoftPhongShader(
        device=device, 
        cameras=cameras,
        lights=lights
    )
)

images = renderer(mesh)
# plt.figure(figsize=(10, 10))
plt.imshow(images[0, ..., :3].cpu().numpy())
plt.show()

plane.obj and plane.mtl

mtllib plane.mtl
o Cube
v 0.5  0.5 0.0
v -0.5  0.5 0.0
v 0.5  -0.5 0.0 
v -0.5  -0.5 0.0
vt 0.0 1.0
vt 1.0 1.0
vt 0.0 0.0
vt 1.0 0.0
usemtl material_1
s off
f 4/3/1 1/2/1 2/1/1
f 4/3/1 3/4/1 1/2/1

newmtl material_1
map_Kd banana.jpg

# Test colors

Ka 1.000 1.000 1.000  # white
Kd 1.000 1.000 1.000  # white
Ks 0.000 0.000 0.000  # black
Ns 10.0

banana.jpg 3. The exact command(s) you ran: python render.py

5. What you observed (including the full logs): there is a seam between the two triangles.

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This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[github-actions[bot]]

This issue was closed because it has been stalled for 5 days with no activity.

[kjchalup]

Thanks for reporting and great repro steps!

I checked that the seam disappears if you change to blur_radius=1e-5. Also, there's no blur if you use the new MeshRasterizerOpenGL (though you need pycuda.gl and pyopengl for that!).

Nevertheless, this looks like a bug in MeshRasterizer -- it shouldn't be leaving holes even with blur_radius=0.0. I'll try to look into it when I get some time.