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Metaball disappears when deleting first metaball object
Closed, ResolvedPublic

Description

System Information
Operating system and graphics card

Problem seems to be independent of graphics card and OS.
Have tried on OS X (intel) and different combinations of windows/linux and intel/nvidia cards.

Blender Version
Broken: 2.79 rc1 (and at least a couple of releases back)
Worked: not sure which release, but it did work before

Exact steps for others to reproduce the error

Bug is easy to reproduce, so no blend-file is attached.
There are in fact two problems described here, but I assume they are closely related.

Problem 1:

  • create two separate metaball objects
  • delete first object
  • all generated metaball meshes disappears from view,
  • problem persists after metaball object is moved, and also after save/reload

Problem 2:

  • create two separate metaball objects
  • delete second object
  • both metaball meshes are still shown
  • problem disappears when a metaball object is moved / refreshed

Event Timeline

It disappears on me as well, I will take a look!

There is so called "motherball", which contains actual tessellation of all related metaballs. It is calculated as simple as dropping possible ".001" and such suffixes. For example, motherball for "MyMeta.001" will be "MyMeta", and "MyMeta" will contain tessellation for all "MyMeta.001", "MyMeta.002" and so on. If you remove motherball you'll have nowhere to store tessellation. Not saying it's intuitive, but it's how things works.

Missing update was introduced by rB897e97f.

@Bastien Montagne (mont29), we "just" need to have DEG_id_tag_update somewhere, at lest that's my guess :)

Sergey Sharybin (sergey) changed the task status from Invalid to Unknown Status.Aug 10 2017, 11:25 AM

@Campbell Barton (campbellbarton), re-opening. The second issue is a real bug.

Sergey Sharybin (sergey) lowered the priority of this task from 90 to 50.Aug 10 2017, 11:25 AM