cloth simulation, rest shape key does not function. #40053

New Issue

Jim Gaston · 2014-05-06T22:19:07+02:00

Jim Gaston commented

2014-05-06 22:19:07 +02:00

System Information
Windows/8 64 bit
GeForce GT 640

Blender Version
Broken:
(2.70 19e627c)
(2.62 r44136)

Worked:
(2.61)

Short description of error

the cloth modifier, on the physics tab,
has a "Rest Shape Key".

The field is only visible when the object has shape keys.

The rest shape key allows the fabric to have an initial position that is different from the shape of the fabric.

when a shape key is created, and attached to the fabric modifier,
it does not initialize the fabric springs in the cloth simulator.

Exact steps for others to reproduce the error

load the attached blend file and start the animation (play button or "alt a")
gravity is turned off.
only fabric springs will animate.
the rest spring length, specified by the rest shape key, are shorter than the starting locations.

on release 2.61,
the fabric will moves to shorten the springs.
(after a few frames the fabric will have a U shape.
This is not a morph. It occurs because of the cloth physics recognizes a stretched spring and pulls the fabric together).

on release 2.62 or later (up to and including 2.70)
the fabric will do nothing.

Running blender.exe in the debugger:
module: blenkernel\intern\cloth.c
the function call
shapekey_rest = dm->getVertDataArray ( dm, CD_CLOTH_ORCO );
returns null.

cloth.blend

**System Information** Windows/8 64 bit GeForce GT 640 **Blender Version** Broken: (2.70 19e627c) (2.62 r44136) Worked: (2.61) **Short description of error** the cloth modifier, on the physics tab, has a "Rest Shape Key". The field is only visible when the object has shape keys. The rest shape key allows the fabric to have an initial position that is different from the shape of the fabric. when a shape key is created, and attached to the fabric modifier, it does not initialize the fabric springs in the cloth simulator. **Exact steps for others to reproduce the error** load the attached blend file and start the animation (play button or "alt a") gravity is turned off. only fabric springs will animate. the rest spring length, specified by the rest shape key, are shorter than the starting locations. on release 2.61, the fabric will moves to shorten the springs. (after a few frames the fabric will have a U shape. This is not a morph. It occurs because of the cloth physics recognizes a stretched spring and pulls the fabric together). on release 2.62 or later (up to and including 2.70) the fabric will do nothing. Running blender.exe in the debugger: module: blenkernel\intern\cloth.c the function call shapekey_rest = dm->getVertDataArray ( dm, CD_CLOTH_ORCO ); returns null. [cloth.blend](https://archive.blender.org/developer/F87332/cloth.blend)

Jim Gaston commented

2014-05-06 22:19:07 +02:00

Changed status to: 'Open'

Jim Gaston commented

2014-05-06 22:19:07 +02:00

Added subscriber: @JimG

Campbell Barton self-assigned this 2014-05-06 22:26:42 +02:00

Campbell Barton removed their assignment 2014-05-07 02:49:15 +02:00

Sergey Sharybin was assigned by Campbell Barton

2014-05-07 02:49:15 +02:00

Campbell Barton commented

2014-05-07 02:49:15 +02:00

Added subscribers: @Sergey, @ideasman42

Campbell Barton commented

2014-05-07 02:49:15 +02:00

@Sergey, this bug is caused by: 5d49eff25a, fix for #29957

eModifierTypeType_Nonconstructive -> eModifierTypeType_OnlyDeform

Now mesh_calc_modifiers handles the cloth modifier without adding CD_CLOTH_ORCO.

Adding CD_CLOTH_ORCO in the if (useDeform) { loop isnt so simple since at this point its assumed theres no dm pointer (only deform vert array)

@Sergey, this bug is caused by: 5d49eff25a, fix for #29957 `eModifierTypeType_Nonconstructive` -> `eModifierTypeType_OnlyDeform` Now `mesh_calc_modifiers` handles the cloth modifier without adding `CD_CLOTH_ORCO`. Adding CD_CLOTH_ORCO in the `if (useDeform) {` loop isnt so simple since at this point its assumed theres no `dm` pointer (only deform vert array)

Bastien Montagne commented

2014-05-10 08:27:33 +02:00

Added subscriber: @mont29