**System Information**
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68
**Blender Version**
Broken: version: 3.0.0 Alpha, branch: cycles-x, commit date: 2021-09-02 10:34, hash: `rBb72c1e93247f`
Also Broken with the Blender 2.93 version.
**Short description of error**
Solid emitters aren't solid. They have an empty interior even if you put the [[ https://docs.blender.org/manual/en/dev/physics/fluid/type/flow.html#bpy-types-fluidflowsettings-volume-density | Volume Emission ]] setting to 1.
**If the cache type is set to UniCache it fixes this problem.**
Emitter settings:
{F10375022}
Viewport 2D slice:
{F10375025}
Render with default volume shader settings:
{F10375027}
**Exact steps for others to reproduce the error**
# Create a gas domain from a cube
# Only increase the resolution for a better view and change the cache type to modular and resumable
# Create an emitter from a cube
# Only change the Flow source settings
# Set the "Surface Emission" to 0.0 and "Volume Emission" to 1.0
# Bake the simulation and inspect it using the viewport slice option.
Based on an attached .blend file
{F10375014}