Describe the bug
Iron bars, glass pane and chain is not rendered in world preview, only appear inside the book.

Note: colored glass panes are shown.

To Reproduce
Steps to reproduce the behavior:

1. Have multiblock in modonomicon with one of these blocks (used occultism last pentacle)
2. Click Eye Button
3. Place in world
4. See error

Expected behavior
Render these blocks in placed preview

Screenshots

System (please complete the following information):

• Modonomicon Version: 1.108.1
• OS: Windows 10
• Minecraft Version: 1.21.1
• Modpack Link and Version, or list of mods:
  

Thanks for reporting!
I wonder why these are not rendering, as currently the rendering uses the vanilla block renderer for both places. I need to do some testing, maybe it is about the render state setup

On second thought, the colored glass panes might be hint that the render type is different and somehow does not render cutout (only "true" transparency)

Yes, the problem is the transparency rendering of the multiblock preview. It adds "enableBlend" and an alpha value to the render types. For cutout that leads to no rendering at all. I will check with smarter people if this can be counteracted

Next update will fix this, but e.g. glass panes are not great blocks to use in multiblocks as they are very dependent on blockstate. Their default blockstate basically just renders one 3d pixel at the top and one at the bottom