MultiMeshBaker

MultiMeshBaker is a free Godot 3.4+ Plugin, which allows you to merge multiple MeshInstances referencing the same 3d model data into one MultiMeshInstance node. That way you are able to do precise placements of multiple objects, while also benefiting from the increased speed of rendering them via instancing.

Overall you are able to define custom positions, rotation, scale and albedo_color for each instance. The plugin has a simple and straight forward implementation, so it can be easily extended depending on your needs.

The MultiMeshBaker Plugin has an implementation for baking MeshInstances into a MultiMeshInstance, as well as MeshInstance2Ds into MultiMeshInstance2D.

Install:
Create an addons folder in you project directory and extract the contents of the download in there. Then open your project in Godot.

Go to "Project" -> "Project Settings" -> "Plugins" and enable the plugin there.

You now have a new type of node available in your Project: MultiMeshBaker.

Use:
Add the MultiMeshBaker node to your scene, click on it and look in the inspector tab. From there you can create MultiMeshInstance nodes, by first creating multiple MeshInstance nodes of the same type and positioning them. To instantiate MeshInstance nodes assign a template mesh first. Then click on "Add Mesh Instance" for every instance you want to add.

When you want to bake the MeshInstance nodes to a single MultiMeshInstance node, click "Bake". You can also unbake an existing MultiMeshInstance node, by assiging it to "Unbake MultimeshInstance path" and clicking "unbake".

Licence:

You are allowed to use this plugin for free and commercial projects made with Godot Engine.
You are NOT allowed to redistribute the files of this plugin or their contents.
The plugin was made and released by Martin Senges.
You are NOT allowed to claim authorship of the files provided in this plugin or the plugin itself.
In no event shall the author of the plugin be liable for any claim, damages or other liability, arising from the inclusion of the plugin in a project or it's actual use.