You can’t create meshes inside Roblox Studio, but you can create them inside Blender 3D (and export them into your ... there are many free, prebuilt models out there if you don't feel like ...

Cube’s 3D mesh generation ... the in-game item within Roblox Studio. The open source version of Cube 3D allows anyone to customize, create plug-ins, or train the model with their own datasets ...