By default skeletal mesh use Capsule shadows, This means setting up a Physics Asset specifically to handle shadow casting rather than casting from the mesh directly.
While the template Sandbert mesh comes with a physics asset assigned for this purpose, you will need to add your own to any additional mesh effects, articles or other Skeletal Mesh that you import.
The shadow casting physics asset is not the same as the Default or Hurtbox Physics Assets, it is a third unique asset tuned specifically for shadow casting purposes. While it is possible to reuse a physics asset for more than one use it’s good practice to keep them separate so you can adjust them for their independent needs.
Create a Shadow Physics Asset
- Generate physics asset on import, or if you failed to do so…
- Navigate to your character’s skeleton in the Content Browser, right-click, and select Create > Physics Asset > Create.
- Set the Minimum Bone Size to a value like to ensure capsules are generated for main limbs.
- Refine the capsules in the Physics Asset editor to cover the character snugly.
- Try to keep your capsule count between 10-20 focusing on areas near the feet primarily and only capturing major forms, ignore fingers toes etc.
Assign the Shadow Physics Asset
- Open your mesh’s Skeletal Mesh asset.
- In the Details panel, find the Lighting section.
- Assign the newly created Physics Asset to the Shadow Physics Asset slot.
If your joints are imported with scaling on them either from values left in blender or using import scale adjustments you may run into issues where the shadow is either much bigger than expected or so small that you cannot see it giving the impression that it just isn’t casting.
In this case the only solution some have found so far is compensating by adjusting your capsule scale however this is a convoluted workflow that we do not support.
If you have corrected your scale with import scale values other than 1 consider instead setting it back to 1 and changing your export scale in blender to correct for scale issues.