Creating Custom Blocks
From Eco - English Wiki
This page will walk you through the basics of adding custom blocks to Eco utilizing the Glass models found already in the game to make a Green Stained Glass block. A completed tutorial can be here as well as the asset files needed to complete this tutorial.
https://github.com/StrangeLoopGames/EcoModKit/tree/examples/Examples/Blockset
Initial Scene Setup
Creating your BlockSet
Creating your first BlockBuilder
Common Bugs
Below are a list of common bugs encountered while making custom blocks/blocksets and how to solve them.
My block does not appear using the right mesh or in the spot I placed it.
This should be automatically handled in 9.4's ModKit. However if the issue is still present uncheck the "Optimize Mesh Data" option inside Unity's Player Settings prior to exporting the mesh.