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MSFS Blender cloth simulation baked to bones

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330
Country
austria
HowTo do a cloth animation baked to bones exported to msfs:

Start with a cylinder and add some segments
2021-03-03 20_06_15-Window.jpg


Add a armature in the middle of the cylinder and place the tips of each bone at one segment. There has to be one bone at the beginning of the cylinder.
2021-03-03 20_10_25-Window.jpg


Add a vertex group for every segment of the cylinder and a pin group
2021-03-03 20_10_43-Window.jpg


Assign each segment ring to one vertex group and the first two segments are the pin group
2021-03-03 20_11_08-Window.jpg


After that select the armature and go to pose mode. Select the first bone and go to the constrains menu. Select inverse kinematics.
2021-03-03 20_12_59-Window.jpg


Set the target to the cylinder and the vertex group to that group that is at the tip of the bone. Set the chain length to 1
2021-03-03 20_13_36-Window.jpg


Do this for every bone
2021-03-03 20_14_06-Window.jpg


2021-03-03 20_15_48-Window.jpg


Here comes the pin group forgot that earlier.
2021-03-03 20_16_16-Window.jpg


After that set some physics to the cylinder. Add a cloth physic. And adjust the settings.
2021-03-03 20_17_12-Window.jpg
 
Messages
330
Country
austria
Set the pin group in the shape settings of the cloth physics
2021-03-03 20_17_45-Window.jpg


I used this settings for a test
2021-03-03 20_23_39-Window.jpg


Add a force field Wind and set the strength to 500 rotate it that the force go right through the cylinder.

Run the animation in the timeline. Now you see the cylinder moving in the wind and the bones following the cylinder. Find a sweet spot where the animation is smooth running in a loop circle without big jumps at the end. Limit the frames to this sequence. Mine was from 140 - 173

2021-03-03 20_25_31-Window.jpg


Select the armature and go to pose mode. Select all bones.

2021-03-03 20_26_01-Window.jpg


Click on Pose/Animation/Bake Action
2021-03-03 20_26_24-Window.jpg


Check the first 3 Checkboxes and hit OK
2021-03-03 20_26_40-Window.jpg


Now you got the keyframes.
2021-03-03 20_27_04-Window.jpg


Remove the cloth physics from the cylinder and delete the force field (no longer needed)
2021-03-03 20_27_49-Window.jpg


Parent the cylinder to the armature.
2021-03-03 20_28_15-Window.jpg


Select the armature and then the cylinder (that the cylinder is the active object)
2021-03-03 20_28_56-Window.jpg
 
Messages
330
Country
austria
Switch to weight paint mode.
2021-03-03 20_29_27-Window.jpg


Set the falloff to constant (then you get a weight of 1 with one click)
2021-03-03 20_29_54-Window.jpg


Shift click on the first bone then paint the vertex on the tip with a weight of 1.

2021-03-03 20_31_56-Window.jpg


And move on like this.
2021-03-03 20_32_20-Window.jpg


Shift click the second and paint the next ring.

Switch the view to paint the vertex on the backside too. It looks like that even in wireframe view you don’t get them. So you have to rotate the view to paint them.
2021-03-03 20_35_08-Window.jpg


after finishing the weight painting. Go to the dope sheet action editor and push down the animation to the nla track.
2021-03-03 20_41_52-Window.jpg


The last step before exporting and most important one to remove the distortions in the sim.

Add an empty (I always use plain axis).

Select the armature and the cylinder and last the empty (with shift klick).

The empty should be the active opject. Now parent the armature and the cylinder to the empty. Parent/object.
2021-03-04 19_57_48-Blender_ [E__Gaming Assets_BlendFiles_Mikeaat-AssetPack_Windsock_Mikeaat-W...jpg


Select all 3 parts and export it as usual.
2021-03-03 20_43_18-Window.jpg


Edit the xml to integrate the animation.

Compile the pack and enjoy
 
Messages
57
Country
france
Thanks for this very well documented tutorial :)

I tried it, and it works pretty nice exept is not close to real in game since the animation makes the mesh doing some weird flex lol
Anyway, I'm gonna use 3DS max now for such animations

Thanks a lot again :)
 
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330
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austria
Sounds crazy, with this approach i get a animation in the game 95% like in blender Without any crazy mesh distortions. :)
 
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266
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unitedkingdom
Superb tutorial, thanks.

How do we get from here to making it react to wind direction in MSFS?

Sent from my SM-T813 using Tapatalk
 
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222
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germany
Sorry if this is a stupid question, but I don't understand the process of exporting animated objects. If I do the things you described I get a single gltf, bin and XML file for the animated model, but shouldn't there be separate files for the model and the animation with an xml entry that links the animation GUID to the model GUID? Could you please show a screen shot of the export folder containing the exported files? Thank you!
 
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330
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austria
The animation is in the normal files included. There is a good tut on youtube about the basic animation process.
 
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222
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germany
The animation is in the normal files included. There is a good tut on youtube about the basic animation process.
Thank you, I was able to export the animation successfully into the sim, but as someone else stated above, I get massive mesh distortions . It seems the effect of the armature on the mesh is vastly exaggerated in the sim compared to Blender even if I parent the armature and object to an empty.
Screenshot (134).png
Screenshot (132).png
 
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330
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austria
your parent to the empty is wrong the mesh and the armature hase to be on the same level in the outliner. your mesh is one step deeper. :)
you have to select your mesh and the armature and parent it to the empty.
 
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222
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germany
You're right, it's working now though it's rotated 90 degrees upwards, but I can correct that. Do you know why the empty is needed for the animation to display correctly? Seems a little counterintuitive.
 
Messages
330
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austria
No not really, seems like msfs is reading the gltf different than default gltf viewers do.
 
Messages
166
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germany
Hi, thank you very much for these instructions!
If you do this for a flag - do you also use "inverse kinematics" and assign a vertex group for each vertical edge?

1617442293488.png


EDIT: I already answered for myself that this is not working... But I do not yet know how it would work. :(
 
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Messages
117
Country
unitedstates
@Mikea.at, thank you for this. This technique helps produce much more realistic animations than I can by hand! Wonderful!

@karlo922, I cannot tell by your screenshot but have you put horizontal loop cuts behind each row of bones? I was able to get this to work on a flag to produce a nice rolling effect from the top to the bottom. I assigned each vertex to its own vertex group. And then weight painted each bone to a vertex group.

The only frustrating part of this technique is that you have to recreate the IK modifier for each animation that you want to include with the object. So, if you want to have a limp flag, a slowly waving flag, a fast waving flag and a stiff flag, it requires recreating the IK modifier several times. For a complex flag, this can take some time! Nevertheless, this has improved the quality of my cloth objects considerably!


Sent from my iPhone using Tapatalk
 
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Messages
166
Country
germany
Hi,
thank you! For re-assigning the vertex group to the bone constraints, I wrote a small python script which you can easily adjust and include inside blender:

It works if your bones have the names:
- "Bone", "Bone.001", "Bone.002" ...
and the Vertex Groups:
- "1", "2", ...

You need to tell it what is your target mesh name and how many bones you have in the first lines. Then it will go through all your bones and assign the Vertex group to it. Saves really much time :)
It works for me if I'm in Pose Mode and each Bone shall be assigned to one Vertex which is also one VertexGroup. Like you proposed.

1617524193642.png


Code:
# --- SOME DEFINITIONS ------------------------------
NameOfTarget = "EDSP_Flagge" # insert Target Mesh name
TotalNumberBones = 65 #insert total number of bones
BoneCounter = 0 #start value, will work with bone names: Bone, Bone.001, Bone.002, ...
#---------------------------------------------------

import bpy
while BoneCounter <= TotalNumberBones:
    if BoneCounter == 0: #first bone simply called "Bone"
        BoneString = "Bone"
    elif BoneCounter < 10: #make sure to have correct count of "0" in name
        BoneString = "Bone.00"+str(BoneCounter)
    elif BoneCounter < 100:
        BoneString = "Bone.0"+str(BoneCounter)
    else:
        BoneString = "Bone."+str(BoneCounter)
    
    VertexString = str(BoneCounter+1) # Vertex is always one number greater, e.g. Bone.001 -> VertexGroup 2
    #print(BoneCounter)
    #print(BoneString)

    #Do it!
    o=bpy.context.object
    b=o.data.bones[BoneString]
    b.select=True
    o.data.bones.active=b
    bpy.ops.pose.constraint_add(type='IK')
    bpy.context.object.pose.bones[BoneString].constraints["IK"].target = bpy.data.objects[NameOfTarget]
    bpy.context.object.pose.bones[BoneString].constraints["IK"].chain_count = 1
    bpy.context.object.pose.bones[BoneString].constraints["IK"].subtarget = VertexString

    #Next bone
    BoneCounter=BoneCounter+1
 
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