3D View alpha channel transparency behaviour changes depending on object creation order #55130

New Issue

sok0 · 2018-05-20T01:45:49+02:00

sok0 commented

2018-05-20 01:45:49 +02:00

The alpha channel transparency behavior masks older objects while allowing newer objects to be seen.

In other words, If you create a Cube first, then a plane with alpha transparency the plane masks the cube from view.

But

if you create a plane with alpha transparency then a cube, the cube is not masked.

Furthermore

If you create a Cube first, then a plane with alpha transparency the plane masks the cube from view. Then if you duplicate the cube, the duplicated cube is not masked. Then if you duplicate the plane, it masks everything again.

In the attached example, Cube was created first, Then Plane, Then Cube.001, Then Plane.001, Then Cube.002.

Additionally, behavior changes when objects are selected. In the above described example no objects are selected. Selected cubes are always masked by planes with alpha transparency. Selected planes never mask cubes.

It looks like there was an attempt at some point to remedy this problem by adding Object data Display Transparency option. However this has other undesirable consequences like elimination of the selection outline.

The default behavior is illogical. Requiring objects to be duplicated in the order that you want them shown is not logical. The behavior changing depending on object selection is also illogical; why would you want an object to disappear when it is selected?alpha transparency.blend

The alpha channel transparency behavior masks older objects while allowing newer objects to be seen. In other words, If you create a Cube first, then a plane with alpha transparency the plane masks the cube from view. But if you create a plane with alpha transparency then a cube, the cube is not masked. Furthermore If you create a Cube first, then a plane with alpha transparency the plane masks the cube from view. Then if you duplicate the cube, the duplicated cube is not masked. Then if you duplicate the plane, it masks everything again. In the attached example, Cube was created first, Then Plane, Then Cube.001, Then Plane.001, Then Cube.002. Additionally, behavior changes when objects are selected. In the above described example no objects are selected. Selected cubes are always masked by planes with alpha transparency. Selected planes never mask cubes. It looks like there was an attempt at some point to remedy this problem by adding Object data Display Transparency option. However this has other undesirable consequences like elimination of the selection outline. The default behavior is illogical. Requiring objects to be duplicated in the order that you want them shown is not logical. The behavior changing depending on object selection is also illogical; why would you want an object to disappear when it is selected?[alpha transparency.blend](https://archive.blender.org/developer/F3398773/alpha_transparency.blend)

sok0 commented

2018-05-20 01:45:49 +02:00

Added subscriber: @sok0

sok0 commented

2018-05-20 01:49:39 +02:00

uploaded the wrong file... use this one instead{F3398841}

uploaded the wrong file... use this one instead{[F3398841](https://archive.blender.org/developer/F3398841/alpha_transparency.blend)}

Philipp Oeser commented

2018-05-22 12:13:49 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2018-05-22 12:13:49 +02:00

Alpha sorting was a long-standing 'problem' but it will be fixed in 2.8.
This has been reported a couple of times, see #43093, #51964, #46349, #49376, #44826, #41731

But there is a workaround though of the top of my head:

parent all of your objects to an empty
unparent them in the desired drawing order
voila, proper drawing order is restored :) [have a look at this tutorial https://www.youtube.com/watch?v=4mSGOTaoCgM]

I guess consensus here was to close these reports as 'wont fix in 2.7' ... and enjoy eevee in 2.8 :)

Alpha sorting was a long-standing 'problem' but it will be fixed in 2.8. This has been reported a couple of times, see #43093, #51964, #46349, #49376, #44826, #41731 But there is a workaround though of the top of my head: - parent all of your objects to an empty - unparent them in the desired drawing order - voila, proper drawing order is restored :) [have a look at this tutorial https://www.youtube.com/watch?v=4mSGOTaoCgM] I guess consensus here was to close these reports as 'wont fix in 2.7' ... and enjoy eevee in 2.8 :)

Philipp Oeser commented

2018-05-22 12:14:21 +02:00

Closed as duplicate of #43093

Philipp Oeser closed this issue

2018-05-22 12:14:21 +02:00

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3D View alpha channel transparency behaviour changes depending on object creation order #55130