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First object back of a second transparent object is not visible in Viewport with Material Viewport Shading
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System Information
Windows 7 64-bit
Intel(R) HD Graphics

Blender Version
Broken: Blender 2.78c

Short description of error
1st: Add a few cubes.
2nd: Add a very big transparent plane above those cubes such as the plane covers the cubes.
3rd: Add a few cubes below the plane such as those cubes are covered by the plane.
Don’t forget to deselect all.
By using of Material Viewport Shading, all the cubes added during the 1st step are hidden, but the cubes added during the 3rd step are shown.
Conclusion: All the objects created before the transparent plane are hidden but all the objects created after the transparent plane are shown.

Exact steps for others to reproduce the error

  1. File > New (Don’t delete the default cube)
  2. Add a Plane.
  3. With the selected Plane, press G to grab it, then press Z, then press 2, and then press Enter.
  4. With the selected Plane, press S to scale it, then press 4, and then press Enter.
  5. Select the Cube then press Shift+D, then press Y, then press 3, and then press Enter.
  6. At the bottom of the 3D View area, click on the white sphere icon to change the Viewport Shading into Material.
  7. Select the Plane, then go to the Material context in the Properties and then add a new Material.
  8. Check the Transparency panel check box to enable it.
  9. In the Transparency panel, change the Alpha to 0.5
  10. Move your mouse on the 3D View area then press A to deselect all.
  11. Error: The top part of the first cube is not visible because it’s created before the plane and it’s back of the transparent plane, but why the second cube which is created after the plane is completely visible?

Remark: If you select the transparent plane then you can’t see the error, but you must deselect the plane.



Event Timeline

Aaron Carlisle (Blendify) triaged this task as Needs Information from User priority.

Thanks for the report but it would be helpful if you add a blend-file to the report that demonstrates the issue at hand.

OK, these are some blend-files to the report:

Aaron Carlisle (Blendify) raised the priority of this task from Needs Information from User to Needs Triage by Developer.May 22 2017, 5:23 PM
Sergey Sharybin (sergey) closed this task as Archived.
Sergey Sharybin (sergey) claimed this task.

For transparency working reliably it is needed to have face sorting of some sort, otherwise object draw order might be wrong and cause artifacts like that.

This is something to be looked for PBR viewport of Blender 2.8, but it will unlikely be fixed in the current viewport code.

Thanks for the report, but it's a know limitation which is not considered a bug currently.