rendering problems with mesh3d and logarithmic zaxis
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bug
P3
- Dominant language
- Python
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Description
I'm trying to visualize a 3D bar chart, in which I need a logarithmic z-axis. However, I've stumbled upon a rendering problem: only the top size of the cube is rendered.
import numpy as np
import plotly.graph_objects as go
Percentage_Differences_1 = np.array([ [7.94*(10**-10),7.94*(10**-9),7.94*(10**-8),7.94*(10**-7),7.94*(10**-6),7.94*(10**-5)],
[7.92*(10**-12),7.92*(10**-11),7.92*(10**-10),7.92*(10**-9),7.92*(10**-8),7.92*(10**-7)],
[7.72*(10**-14),7.72*(10**-13),7.72*(10**-12),7.72*(10**-11),7.72*(10**-10),7.72*(10**-9)],
[5.66*(10**-16),5.66*(10**-15),5.66*(10**-14),5.66*(10**-13),5.66*(10**-12),5.66*(10**-11)],
[1.49*(10**-17),1.49*(10**-16),1.49*(10**-15),1.49*(10**-14),1.49*(10**-13),1.49*(10**-12)],
[2.21*(10**-18),2.21*(10**-17),2.21*(10**-16),2.21*(10**-15),2.21*(10**-14),2.21*(10**-13)] ])
bar_verts = np.array([[0, 0, 0, 1],
[1, 0, 0, 1],
[1, 1, 0, 1],
[0, 1, 0, 1],
[0, 0, 1, 1],
[1, 0, 1, 1],
[1, 1, 1, 1],
[0, 1, 1, 1]], dtype=float).T
def translate(x, y, z):
d = np.eye(4, dtype=float)
d[:, -1] = [x, y, z, 1]
return d
def scale(sx, sy, sz):
d = np.eye(4, dtype=float)
d[np.diag_indices(4)] = [sx, sy, sz, 1]
return d
meshes = []
for xc in range(1,6):
for yc in range(1,6):
verts = np.matmul(translate(xc, yc, 0), bar_verts)
verts = np.matmul(scale(1, 1, Percentage_Differences_1[xc][yc]), verts)
x = verts[0, :]
y = verts[1, :]
z = verts[2, :]
meshes.append(
go.Mesh3d(
x=x, y=y, z=z,
# i, j and k give the vertices of triangles
i = [7, 0, 0, 0, 4, 4, 6, 6, 4, 0, 3, 2],
j = [3, 4, 1, 2, 5, 6, 5, 2, 0, 1, 6, 3],
k = [0, 7, 2, 3, 6, 7, 1, 1, 5, 5, 7, 6],
flatshading = True
)
)
fig = go.Figure(data=meshes, layout={
"scene": {
"zaxis": {
"type": "log"
}
}
})
fig
Here is a screenshot: on the left, linear z axis. On the right, logarithmic z axis.

Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the supplied Python example with plotly.graph_objects.Mesh3d and compare the linear and logarithmic z-axis renders. Start by tracing Mesh3d rendering with logarithmic scene axes; done means the complete set of 3D bars renders correctly with the logarithmic z-axis, while preserving the linear-axis behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- data-visualization
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100