Layer numbers differ from Describe.txt
Symptom
You open Describe.txt from your HueForge project. It lists color
changes at, say, layers 8, 16, 24, 32. You open the exported 3MF
in your slicer and the filament changes show at layers 5, 9, 13, 17.
Did something get lost?
Short answer
No. Describe.txt lists layer numbers without a Height Range Modifier (HRM) applied. The 3MF Export Plugin adds an HRM automatically — it prints the beginning of your HueForge model at a larger layer height to speed up the base. Your slicer’s layer numbers shift compared to Describe.txt as a result, but the filament changes still happen at the right Z heights.
What’s happening under the hood
A HueForge model is conceptually:
- A thick opaque base color at the bottom (your “first layer” stack).
- A series of thin colored detail layers on top.
A naive slice would use one layer height for everything. That means the base — which is just a flat slab and benefits nothing from fine resolution — prints at the same 0.08 mm slow detail height as the colors above it. Wasted time.
The plugin instead writes a layer_config_ranges block (Height Range
Modifier) into the 3MF that says:
From Z=0 up to the top of the base, print at firstLayerHeight (e.g. 0.20 mm). Above that, print at layerHeight (e.g. 0.08 mm).
The slicer obeys: the base uses fewer, thicker layers; the color stack above uses the thin detail layers. Total print time drops significantly, surface quality on the visible top is unchanged.
Why the layer numbers differ
Suppose your filament changes are at Z = 0.8 mm, 1.6 mm, 2.4 mm.
| Without HRM | With HRM (0.20 base, 0.08 detail) |
|---|---|
| 0.08 mm layers throughout | 0.20 mm base layers, then 0.08 mm |
| Z = 0.8 mm → layer 10 | Z = 0.8 mm → layer 4 (3 base + 1 detail) |
| Z = 1.6 mm → layer 20 | Z = 1.6 mm → layer 14 |
| Z = 2.4 mm → layer 30 | Z = 2.4 mm → layer 24 |
The Z heights are identical; the layer indices differ because the base now takes fewer layers.
Describe.txt was generated before the HRM was applied, so it reflects the without-HRM numbering. The 3MF reflects the with-HRM numbering.
How to verify
In your slicer, hover over a filament-change line in the preview. The slicer shows the Z height of that layer. Compare it to the Z column in Describe.txt — they should match exactly.
”Can I turn the HRM off?”
Height Range Modifier (HRM) is currently not a toggle in the export dialog.