René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: 3D scatter plot flips alpha order depending on depth relative to camera","articleBody":"### Bug summary\n\nWhen plotting a 3D scatter plot with multiple alpha values the resulting alpha values that are plotted depend on the order of points relative to the camera. This behavior continues even if depthshade=False is used. The behavior stops if the points are plotted individually using a for loop.\n\n### Code for reproduction\n\n```python\nimport matplotlib.pyplot as plt\r\n\r\nfig = plt.figure()\r\nax = fig.add_subplot(projection=\"3d\")\r\n\r\nX = [i for i in range(10)]\r\nY = [i for i in range(10)]\r\nZ = [i for i in range(10)]\r\nS = [(i+1)*400 for i in range(10)]\r\nA = [i/10 for i in range(10)]\r\n\r\nax.scatter(xs=X, ys=Y, zs=Z, s=S, alpha=A, depthshade=False)\r\n\r\nplt.show()\n```\n\n\n### Actual outcome\n\nEx: In the images below you can see the result of slightly rotating the same plot so that one end of the line of points is closer or further from the camera. This causes the list of alpha values to be applied in either the intended order, or the reverse of that order.\r\n \r\n![Screenshot from 2022-04-17 13-37-52](https://user-images.githubusercontent.com/9289200/163736942-0196bfcd-0d30-49fa-9d20-4143e297c4ae.png)\r\n![Screenshot from 2022-04-17 13-38-01](https://user-images.githubusercontent.com/9289200/163736943-c9e76c8c-ef83-4b42-afdb-c19593915390.png)\r\n\n\n### Expected outcome\n\nSimply: the 3D scatter plot alpha values when depthshade=False is used should not depend on the depth from the camera.\n\n### Additional information\n\nI've seen closed issues where something very similar was fixed for old versions of matplotlib (python 2 era), so it looks like this bug has resurfaced?\n\n### Operating system\n\nUbuntu \n\n### Matplotlib Version\n\nmatplotlib 3.5.1\n\n### Matplotlib Backend\n\n_No response_\n\n### Python version\n\nPython 3.9.5\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\npip","author":{"url":"https://github.com/nhansendev","@type":"Person","name":"nhansendev"},"datePublished":"2022-04-18T00:07:46.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":7},"url":"https://github.com/22861/matplotlib/issues/22861"}