IDK
Put the player's Roblox avatar into Garry's Mod so that the avatar participates in Garry's Mod's ordinary player movement, collision and sandbox interaction.
SOURCE-ONLY / UNTESTED.
The Garry's Mod side is implemented as a normal addon. It looks for a compiled player model at:
models/roblox_player.mdl
If present, it assigns that model to the player on spawn.
The Roblox client is not a supported mod-loader target here. Roblox runtime content is delivered to the client as part of its client/server runtime, rather than as a documented local avatar-model file that this GMod addon can safely read. The missing piece is therefore an avatar bridge that supplies the actual player avatar as a GMod-compatible playermodel.
This package deliberately does NOT:
Run this addon in the installed Garry's Mod copy with a compatible avatar model supplied by the eventual bridge. Verify:
Until the avatar bridge is available and those tests pass, this is not a publishable Melty release.