Lattices fails Soft Body Physics #73391

New Issue

Marc Draco · 2020-01-25T19:44:24+01:00

Marc Draco commented

2020-01-25 19:44:24 +01:00

System Information
Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: Intel(R) HD Graphics 520 Intel 4.5.0 - Build 23.20.16.4973

Blender Version
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-20 14:27, hash: 26bd5ebd42
Worked: unknown

Short description of error
Soft body physics do no work correctly on lattices (this is suggested in the manual for deforming complex meshes under SB physics).

Exact steps for others to reproduce the error
In the attached blend, a simple lattice has matching properties to the lattice but while the cube behaves as expected, the lattice collapses.

Separate bug report to be filed for the "goal" bug which is also not respected by the lattice.

lattice-soft-body-bug.blend

**System Information** Operating system: Windows-10-10.0.17763 64 Bits Graphics card: Intel(R) HD Graphics 520 Intel 4.5.0 - Build 23.20.16.4973 **Blender Version** Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-20 14:27, hash: `26bd5ebd42` Worked: unknown **Short description of error** Soft body physics do no work correctly on lattices (this is suggested in the manual for deforming complex meshes under SB physics). **Exact steps for others to reproduce the error** In the attached blend, a simple lattice has matching properties to the lattice but while the cube behaves as expected, the lattice collapses. Separate bug report to be filed for the "goal" bug which is also not respected by the lattice. [lattice-soft-body-bug.blend](https://archive.blender.org/developer/F8301628/lattice-soft-body-bug.blend)

Marc Draco commented

2020-01-25 19:44:24 +01:00

Added subscriber: @MarcD

Marc Draco commented

2020-01-25 19:47:21 +01:00

Apologies, "goal" bug has already been fixed.

Fix #26876: Soft Body ignores Goal on Lattice

Apologies, "goal" bug has already been fixed. Fix #26876: Soft Body ignores Goal on Lattice

Richard Antalik commented

2020-01-27 15:38:57 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Jacques Lucke commented

2020-01-29 11:29:49 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2020-01-29 11:29:49 +01:00

Changed status from 'Confirmed' to: 'Archived'

Jacques Lucke closed this issue

2020-01-29 11:29:49 +01:00

Jacques Lucke self-assigned this 2020-01-29 11:29:49 +01:00

Jacques Lucke commented

2020-01-29 11:29:49 +01:00

This seems to work the same as in Blender 2.79. I can make it work by activating Stiffness in your file.

2020-01-29 11-28-56.mp4

Closing because it seems to work as expected.

This seems to work the same as in Blender 2.79. I can make it work by activating `Stiffness` in your file. [2020-01-29 11-28-56.mp4](https://archive.blender.org/developer/F8309620/2020-01-29_11-28-56.mp4) Closing because it seems to work as expected.

Marc Draco commented

2020-01-29 17:08:46 +01:00

Can you reopen this please Jaques?

https://www.youtube.com/watch?v=oKpxOlzv6lc&feature=youtu.be

I'm unsure why it worked with Stiffness in the case I sent you (but I can see that it does here too) but this isn't necessarily the case as I hope is clear from this video.

A copy of the file I've used above is here.

https://drive.google.com/open?id=1CM4fR86kgY7OcGmvhoOhDkBbbDChTZwC

Can you reopen this please Jaques? https://www.youtube.com/watch?v=oKpxOlzv6lc&feature=youtu.be I'm unsure why it worked with Stiffness in the case I sent you (but I can see that it does here too) but this isn't necessarily the case as I hope is clear from this video. A copy of the file I've used above is here. https://drive.google.com/open?id=1CM4fR86kgY7OcGmvhoOhDkBbbDChTZwC

Jacques Lucke commented

2020-01-29 17:12:36 +01:00

Please try setting the Bending parameter to 1.0.

Please try setting the Bending parameter to `1.0`.

Marc Draco commented

2020-01-29 21:28:11 +01:00

That stops the collapse - but the behaviour remains different from the standard cube and is therefore more difficult to predict. Note that the cube does not collapse using a bending value of 0.

The expectation (from a user's point of view) is that a cubic lattice would act per a standard cube - the last time I coded professionally was likely before most of you chaps were born - but even then, user's expectations were high on the list.

This stuff is well above my pay grade but something is off - and it sounds like we're in the land of workarounds - which is fine if we make it clear in the manual or accept this is something that deserves more than a cursory look.

I would note that by default the "goal" is checked and that is confusing to someone coming in blind and trying Soft Bodies since the object just stays there in space rather than falling or deforming.

That stops the collapse - but the behaviour remains different from the standard cube and is therefore more difficult to predict. Note that the cube does not collapse using a bending value of 0. The expectation (from a user's point of view) is that a cubic lattice would act per a standard cube - the last time I coded professionally was likely before most of you chaps were born - but even then, user's expectations were high on the list. This stuff is well above my pay grade but something is off - and it sounds like we're in the land of workarounds - which is fine if we make it clear in the manual or accept this is something that deserves more than a cursory look. I would note that by default the "goal" is checked and that is confusing to someone coming in blind and trying Soft Bodies since the object just stays there in space rather than falling or deforming.

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Lattices fails Soft Body Physics #73391