Interpolate hair curves: Connecting a mask texture breaks the guide curve index of hair curves. (Simple fix by reconnecting one node) #118232

New Issue

SleepyEngi · 2024-02-14T02:57:41+01:00

SleepyEngi commented

2024-02-14 02:57:41 +01:00

System Information
Operating system: Windows 10
Graphics card: rtx 2060 Super

Blender Version
Broken: 4.0.2
Worked: ~

Short description of error
Interpolate hair curves node's guide curves will break if a mask texture is connected. Can be fixed by modifying one connection, pictured underneath.

Exact steps for others to reproduce the error

add an interpolate hair curves node group to a hair object
connect a baldness texture
use the guide curve index to find the guide curves
separate the guide curves
when the texture mask is connected, guide curves disappear. disconnecting it brings them back.

how to visualize hair curves: simply delete geometry if the Index is not equal to the guide curve index

the solution is to reconnect the node group that deletes the points based on the baldness/mask texture as pictured so that it's before the points get handed over to the "Parting IDs" section, as otherwise the delete geometry nodes will cause indexes to change and thus change the indexes, causing the parting IDs to break.

**System Information** Operating system: Windows 10 Graphics card: rtx 2060 Super **Blender Version** Broken: 4.0.2 Worked: ~ **Short description of error** Interpolate hair curves node's guide curves will break if a mask texture is connected. Can be fixed by modifying one connection, pictured underneath. **Exact steps for others to reproduce the error** 1. add an interpolate hair curves node group to a hair object 2. connect a baldness texture 3. use the guide curve index to find the guide curves 4. separate the guide curves 5. when the texture mask is connected, guide curves disappear. disconnecting it brings them back. how to visualize hair curves: simply delete geometry if the Index is not equal to the guide curve index the solution is to reconnect the node group that deletes the points based on the baldness/mask texture as pictured so that it's before the points get handed over to the "Parting IDs" section, as otherwise the delete geometry nodes will cause indexes to change and thus change the indexes, causing the parting IDs to break.

HairFixed.png

246 KiB

NodeBroken.png

197 KiB

visual guides.png

115 KiB

NodeFixed.png

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HairBroken.png

62 KiB

SleepyEngi added the

labels 2024-02-14 02:57:42 +01:00

Pratik Borhade commented

2024-02-16 10:24:15 +01:00

Hi, thanks for the report. Maybe I'm missing something but I didn't completely understand the issue and provided steps. what is "baldness texture"?
Could you attach file?

Hi, thanks for the report. Maybe I'm missing something but I didn't completely understand the issue and provided steps. what is "baldness texture"? Could you attach file?

Pratik Borhade added

Status

Needs Information from User

and removed

Status

Needs Triage

labels 2024-02-16 10:24:40 +01:00

Iliya Katushenock commented

2024-02-16 22:45:15 +01:00

Could you attach file?

Yes, example very needed here.

> Could you attach file? Yes, example very needed here.

Tipsy-ND commented

2024-04-19 22:03:06 +02:00

I stumbled into the exact same issue (and fix) today.

To rephrase it a bit, using a Mask Texture with the Interpolate Hair Curves node breaks the guide_curve_index attribute (no new guides are created after the interpolation part)

Cause (as far as I can tell): Using a mask texture deletes part of the geometry, but the selection of the new guide curves is done with the geometry BEFORE the deletion. Causing an index mismatch when the selection of the new guides is done (resulting in no new guides being selected).

Here's my examples/work file.

The Viewport Node is placed on the geometry at the end of the node and checks which spline is being passed as the Guide Index

Blender 4.1

I stumbled into the exact same issue (and fix) today. To rephrase it a bit, using a Mask **Texture** with the Interpolate Hair Curves node breaks the guide_curve_index attribute (no new guides are created after the interpolation part) Cause (as far as I can tell): Using a mask texture deletes part of the geometry, but the selection of the new guide curves is done with the geometry BEFORE the deletion. Causing an index mismatch when the selection of the new guides is done (resulting in no new guides being selected). Here's my examples/work file. The Viewport Node is placed on the geometry at the end of the node and checks which spline is being passed as the Guide Index Blender 4.1

Interpolation_Mask_Issue.blend

9.7 MiB

MaskAfterFix.png

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MaskBeforeFix.png

93 KiB

NodeFix.png

191 KiB

ViewportNode.png

102 KiB

NoMaskUsed.png

136 KiB

Iliya Katushenock commented

2024-04-19 22:16:02 +02:00

@Tipsy-ND Hi, i still not see the actual issue here, can you attach also example of incorrect result?

Tipsy-ND commented

2024-04-19 23:11:43 +02:00

There is no guide map being passed IF you use a Mask Texture. Meaning you can't use your handplaced curves as guide with other nodes for example.

Here's an example using the Clump node with Existing Guide Map enable.

01: Handplaced curves
02: A Texture Mask
03: Using Interpolate Hair Curve WITHOUT a Texture Mask + Clump Hair Curves using Existing Guide Map [Expected behavior]
04: (Without the Fix) Using Interpolate Hair Curve WITH a Texture Mask + Clump Hair Curves using Existing Guide Map [No Guide Map to be found]
05: (With the Fix) Using Interpolate Hair Curve WITH a Texture Mask + Clump Hair Curves using Existing Guide Map [Expected behavior]

There is no guide map being passed IF you use a Mask Texture. Meaning you can't use your handplaced curves as guide with other nodes for example. Here's an example using the Clump node with **Existing Guide Map** enable. 01: Handplaced curves 02: A Texture Mask 03: Using Interpolate Hair Curve WITHOUT a Texture Mask + Clump Hair Curves using Existing Guide Map [Expected behavior] 04: (Without the Fix) Using Interpolate Hair Curve WITH a Texture Mask + Clump Hair Curves using Existing Guide Map [No Guide Map to be found] 05: (With the Fix) Using Interpolate Hair Curve WITH a Texture Mask + Clump Hair Curves using Existing Guide Map [Expected behavior]

03_ClumpWithoutMask.png

267 KiB

02_Texture Mask.png

105 KiB

04_ClumpWithMask.png

114 KiB

05_ClumpWithMaskFix.png

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01_Handplaced Curves.png

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Iliya Katushenock commented

2024-04-20 09:57:13 +02:00

Please, broken blend file!

Tipsy-ND commented

2024-04-20 22:54:59 +02:00

Here's a cleaner version of the one from my first post.

Default Collection is using the default (as is) Interpolate Hair Curve
Fixed Collection is using the fixed (re-routed) Interpolate Hair Curve

Here's a cleaner version of the one from my first post. Default Collection is using the default (as is) Interpolate Hair Curve Fixed Collection is using the fixed (re-routed) Interpolate Hair Curve

Interpolation_Mask_Issue_2.blend

8.8 MiB

👍 2

Iliya Katushenock commented

2024-04-21 13:29:31 +02:00

Can confirm change and fix. @SimonThommes /

Iliya Katushenock added

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Interpolate hair curves: Connecting a mask texture breaks the guide curve index of hair curves. (Simple fix by reconnecting one node) #118232