Very strong shelf holder, I loaded it 20kg.
It is easy to put on 6-8mm dowels.
The depth of the shelf is 15-20cm.
If you are familiar with Blender, you can customize the model to your liking.
Look last screenshot:
Three array modifiers allow you to make a grid of any size.
Modifier solidify allows you to change the thickness of the walls of the gyroid (default 1.6mm).
Subserf smoothes the grid.
1 Form intersect - defines the outer edge of the entire gyroid.
2 Cube union - the back plate is like an ingot of gold.
3 Hole dawn differense and 3 Hole top differense - forms of holes for fastening.
When done, select Gyroid Shelf and Export. That is, it is not necessary to apply modifiers.
Brim or Raft.
Print only upside down (default orientation).