Collision Filter
发布于：2024-11-21
Functional Interpretation
When limbs are interspersed or too close together in the animation, it can lead to molding or sticking of garments.
Collision filter can set the collision relationship between the garment plate and the human body, and set the human body area of the interspersed part not to collide with the plate, so as to avoid the problem of mold penetration or sticking together.
Version V1.1.0 upgraded the collision filter, by configuring the standard human body collision, you can automatically set the collision filter for the garment.
1. Mapping of human collision zones according to specifications
1.Uninstallation the character's mounted animations and garments to put the character in the default pose
2.Drawing Collision Groups for Characters
Select the mesh body drawing mode
Set the brush to paint the limb area with color
Select RGB channel for the color view mode, set the brush intensity to 1, and set the corresponding brush colors for the limbs as follows:
left Arm | Right Arm | left Leg | Right Leg | left Arm 1 | Right Arm 2 | |
R | 1 | 0 | 0 | 1 | 1 | 0 |
G | 0 | 1 | 1 | 0 | 1 | 0 |
B | 0 | 1 | 0 | 1 | 0 | 1 |
A | 1 | 1 | 1 | 1 | 1 | 1 |
The left and right arms can be drawn with an increased amount of reserve over the joints and a portion of the torso, which improves the correctness of the automatic grouping of the short-sleeve plates.
Check the back of the character as you draw it to prevent missing it.
3.When you're done drawing, click Save
2. Automatically set Collision Filters for garments
1.Automatically set Collision Filters for garments
Mounting a costume to a character in the Style3D component in the initial Apsoe state.
Click on the posefitting to make the garment fit the character accurately.
Click on the Group auto-grouping button and click Save to save it.
2.Run a simulation to validate the Collision Filter
Mount the action for the character, PoseFitting (refer to Character PoseFitting), and run the simulation in the editor to see the effect
The simulation does not show any interpenetration or proximity of limbs that could lead to mold penetration or stick together of garments, i.e., the automatic Collision Filter setting is fine.
Appendix
1.Manual adjustment of Collision Filter
The automatic Collision Filter can be set manually when it doesn't fully address the problems caused by limb interposition, or when there are special collision setting needs.
1.Setting up groups for plates
Click on the selected plate to set the Collison Group in Cloth Pieces.
Based on the body region to which the plate belongs, select the corresponding plate grouping, which ends with the word Cloth.
For body panels that span multiple body regions, such as skirts, you can select multiple groups of panels, such as Left Leg Cloth and Right Leg Cloth for skirts at the same time.
2.Setting the Collision Filter
The Collision Filter shows groups of plates, groups of bodies that collide with them, and groups of plates.
Check Isolate Collsion to display all the plates in this group individually.
Default 5-group Collision Filte.
When a plate belongs to more than one group at the same time, the Collision Filters for each group are valid for that plate.
3.Click Save
Once the settings are complete, click Save and return to the scene to simulate the validation effect.
2.Morgh failure issue after painting Human Collision Zones
When you save after brushing the human collision, the BS deformation control of the skeletal mesh body will be invalidated and you need to manually regenerate it in the UE.
After reconstructing the skeletal mesh body, modifying the deformation controller can be verified to take effect.
3.Metahuman collision mapping
The metahuman character itself uses the RGB channel, so the collision filter needs to be drawn in the Alpha channel.
3.1 Modify the mask color value in the preset
toggle Colliosn Group preset
3.2 Drawing the character mask
Input the color values in the above table and save them after drawing the limbs in order.
4.Body grouping boundary zone mold penetration problem
The shoulder is the boundary area of the body grouping, and problems with molded-in garments can occur in the following situations:
If the hands are interspersed with the Body in the action, you need to manually modify the Collision Filter to set the Arm Plate not to collide with the Body.
At this time, the arm plate does not collide with the Body; the Body plate does not collide with the arm, and once the plate movement exceeds the boundary zone during the movement, mold penetration will occur.
A new transition zone can be added at the boundary to circumvent the problem of mold penetration at the boundary:
1.Collision Group adds new groups
Collision Group select Body1
Setting Color, need other group color different
2.Using the colors above, draw the transition Mask at the border.
5.Group auto-grouping, plates can only be grouped into BodyCloth problem
After the human body is drawn, Group and Save are automatically grouped, and the arm and other parts of the plate are always grouped into BodyCloth.
Make sure that the body area covered by the plate is drawn in place.
The plates are grouped according to the percentage of body area covered, and may be divided into BodyCloth if the arm area is not sufficiently covered.
Coverage ratio is enough but still wrong, check alpha channel match again
Automatic grouping requires that the body RGBA channel values are exactly the same as those defined in the component, and that color areas other than the defined colors that overlay garments are grouped into BodyCloth during grouping
Alpha channel values are easily missed when drawing, Style3D component grouping alpha channel is 1 by default.
When drawing the human body in RGB mode, in the scope of influence as well.
