[TRACKER] Blend shape Issues

[MJacred]

This is a tracker for issues with the Blend shapes implementation in Godot. Blend shapes are also called Shape keys (in Blender) or Morph Targets.

I'm the terror that flaps through the issues! I'm the fly in your released soup. I'm your bad conscience that wakes you at 3am!
I'M the issue tracker!
- a certain duck

Common Workarounds if you have issues

There are two everlasting issues with blendshape meshes and shared instances or mesh resource threaded loading in Godot 3.x so might be one of the two.

a) blend shape values are not (re)set properly when the mesh joins the scene, happens constantly with threading, result is that mesh explodes. You can try to (hard)reset all blend values to e.g. 0.0 in a script and see if this solves the issue.

b) mesh is shared with other instances and not made unique / local to scene. This is not a bug just how Godot rolls with blend shapes. As soon as two instances have different blend values corruption sets in. You can try to duplicate / local_to_scene the mesh for each instance and see if this solves the issue.
(source)

Backlink to the tracker tracker. https://github.com/orgs/godotengine/projects/58/views/3

Godot 4.x

• blend shape operations on ArrayMesh work incorrectly #31595
  • since around Godot 3.2
• Attempted to free invalid ID when using shape keys #75724
• SurfaceTool create_from_blend_shape() creates broken mesh #76320
• EditorSceneImporterMesh does not support default blend shape weights. #49005
  • observed
    • in Godot: 4.0.dev 45d3b96
    • on: Windows10
• Odd behavior in meshes with blendshapes when importing #54719
  • note: crash could not be confirmed
  • observed
    • in Godot: 4.0 (dev/nightly)
    • on GPUs
      • Nvidia GTX 1060 6GB, Nvidia studio driver 471.68 (Windows10)
• Clicking on a blend shape crashes with Toasts #55619
  • observed
    • affects: glb (glTF), unknown for FBX
    • in Godot: 4.0 52b7d5f
    • on GPUs: Nvidia 3000 series, Nvidia GeForce 1060 GTX
    • on: Windows11
• glTF with shapekeys becomes invisible when imported since 4.0alpha2 #58093
  • observed
    • in Godot: 4.0.alpha2.official
    • on: Windows10
• Model Importer treats blend shape tracks as "custom tracks" #68588
• Animation from GLB file not playing properly #75969

Work on Blend shapes in Godot 4

… which might fix issues listed for Godot 3.x (or not)

• glTF: Fix tangent generation for non-blend shapes #37273
  • Cherry-picked for 3.2.2.
• Allow gltf2 morph targets including animations with no default value… #38763
  • Cherry-picked for 3.2.3.
• Allow renaming bones and blendshapes. #42827
  • Cherry-picked for 3.4.
• Reimplement skeletons and blend shapes #44430
• Fix blendshapes and calculation of bone_aabbs #44649
• Accomodate blend shape ranges of -1 to +1 for Vulkan #45859
  • backported to GLES3 in Godot 3.3
• gltf: Fix mesh nodes which are also bones. #48915
• GLTF for game templates. #52802
• Fix auto LOD generation for blendshapes #53608
• gltf export: Fix export of skeletons and skins. #53114
  • in scene gltf export: support blend shapes
  • plus fixes: gltf export: Fix export of skeletons and skins. #53114
  • backported to 3.4 ([3.x] gltf export: Fix export of skeletons, skins and blend shapes #53448)
• Implement Animation Blend Shape Tracks #53865
  • note: Blend shapes are imported via this new track type + several processing optimizations
  • can be exported: glTF export for new TYPE_BLEND_SHAPE tracks #58711
• Fix BLEND_SHAPE_MASK #57801
• Add GLTF, DAE and FBX importers enforcement for blend shape mask array #59489
• Fix normal and tangent blending in blend shapes #61217

Godot 3.x

All sightings are in GLES3, except documented otherwise.

NOTE: I also listed already closed issues, but only if they are cherry-picked for 3.4.x from 3.5 (which not released at the time of writing). There are several closed issues with milestone 3.4 not listed here.

General

• related/duplicate issues due to sharing the same underlying mesh resource
  • Blend shapes glitches in the event that the node is duplicated #10402
    • observed
      • in Godot: 3.0 Alpha1 (on: Ubuntu16.04), 3.2.2, 3.3.2
  • Blend shape glitch after programmatically changing values #51860
    • observed
      • in Godot: 3.3.stable
      • on: Nvidia RTX 2070 (Windows10)
  • Mesh with blendshapes flickers explosion shapes when there exists other mesh instance #61533
    • context: .GLB model which consists of multiple MeshInstances where at least one has blendshapes
    • observed
      • in Godot: 3.4.2stable and 3.5beta
      • on GPU: Intel(R) Iris(R) Xe Graphics (Windows10)
• Issues with Normals
  • Normals are incorrect when applying a blendshape to a skinned mesh #43215
    • affects: glTF
      • but not: FBX; but FBX has the error of not adjusting the normals at all when a blendshape is applied (source)
    • observed
      • in Godot: 3.2.3.Stable
      • on: Inspiron 7373 Core i7-8550U / Intel(R) UHD Graphics 620 (Windows10)
  • Normal map glitches, depth map crashes the driver when blend shape influence set to 1 #42620
    • observed
      • in Godot: 3.2.3.stable (Windows7)
        • on GPU: Nvidia GTX 780
      • in Godot: 3.4.4 (Windows10)
        • on GPU: Nvidia RTX 3060 Ti
      • related [ ] Normals do not work properly with Shape Keys #74228
• Inspector mesh preview rendering glitch when inspecting mesh with blendshapes #54705
  • observed
    • in Godot: 3.4.Stable, 3.5 RC 5, master
    • on: Nvidia GTX 1060 6GB, Nvidia studio driver 471.68 (Windows10)
• Huge blend shape overhead with multiple materials (GLES3) #53244
  • observed
    • in Godot: 3.2, 3.3.2, 3.4.beta
    • on:
      • Nvidia RTX 2080 Ti (Windows10)
      • Nvidia GTX 1050 m (Linux)
• Blendshapes and multi-materials work incorrectly #42242
  • observed
    • in Godot: 3.2.3.stable, 3.5.1.stable
    • on GPU: Intel Iris Plus Graphics (Core i7-1065G7) (Windows10)
    • works on 3.2.3.stable /win10 version 2004 /nvidia 1070 (source) and Godot 3.5.rc8 and Godot 4 Alpha 13 for both Ubuntu; nvidia and Windows 10; nvidia
  • theory: maybe limited to integrated GPUs
  • works in Godot 4.0 beta5 (Vulkan) (source)
• Animation Player + Blend Shapes bug #34658
  • observed
    • in Godot: 3.2 beta 4
    • on: Ubuntu 18.04
  • note: related to / duplicate of Can't Import shape keys animations from Blender using GLTF2 #38443?
• Random visual artifacts with blend shapes on AMD graphics cards (GLES3) #45690
  • affects: .glb, .gltf, .fbx
  • observed
    • in Godot: 3.2.3.stable mono (OS: Manjaro)
    • on GPU: AMD ATI Radeon RX 5600 XT, using video-linux driver
  • could not be reproduced on -> theory: driver issue
    • Godot 3.2.x with GPUs
      • GeForce GTX 1080 (NVIDIA proprietary driver 460.32.03) (OS: Fedora 33)
      • RTX 2070S (Driver version 461.40) (OS: Windows10)
      • Intel HD 630 and AMD Radeon RX Vega M (both with Mesa 20.3.4) (OS: Mageia 8)
• Complex model render incorrectly using GLES3 unless increasing blend shape max buffer size #27390
  • observed
    • in Godot: 3.1 (OS: Windows10), 3.5 RC 6
    • on GPU: AMD Vega 8 and Intel integrated
  • seems to work in GLES2
• Blend shapes have incorrect size on HTML5 platform (GLES3) #60525
  • Cherry-picked for 3.4.5.
  • there was also an issue in GLES2, but it was fixed by [GLES2] Unpack blend shape arrays when necessary #60829
• Get strange black shadow on gltf2 mesh when change camera location and rotation (fixed in GLES3) #58789
  • affects: GLES2
  • Cherry-picked for 3.4.4.
• Godot 3.4.3 Projects created with last minor version do not show materials properly #58592
  • Cherry-picked for 3.4.4.
• Importing glb with Octahedral Compression distorts normals for blend shape with 50% weight #55633
  • Cherry-picked for 3.4.3.
• Mesh Instances randomly not rendering (regression since 3.3) #53374
  • Cherry-picked for 3.4.1.
• Models with blend shape are not rendered correctly (mainly on Android, but also sightings on Desktop with Ubuntu 20.04 using Godot 3.2.stable (source)

HTML

• Shape keys/blendshapes on models imported from Blender cause rendering glitches in HTML builds #63179
  • affects: models in glTF format (both .gltf and .glb) which consists of multiple MeshInstances where at least one has blendshapes
  • observed
    • in Godot: 3.4.4.stable, 3.4.4.mono
    • on Firefox and Google Chrome
    • with GPU: AMD Radeon Vega 8, Driver 24.20.12028.4004 (Windows10)
• Skinned meshes with blendshapes do not render on Android (mainly on Android, but also sightings in HTML (source))

Android

• Problem with Materials in Android #63218
• Models with blend shape are not rendered correctly on Android #39112
  • affected: FBX, unknown for glTF
  • observed
    • in Godot: 3.2.1.stable
    • on GPU: Adreno(TM) 640
    • on phones:
      • OnePlus G1910
      • XIAOMI 8
• Skinned meshes with blendshapes do not render on Android using GLES3 #43217
  • affects: models in glTF and FBX format
  • observed
    • in Godot: 3.2.3.Stable, 3.2.4.rc1, 3.3.4
    • on:
      • Galaxy S6 running android 7.0
      • GPU: Adreno 630 device (POCO F1)

macOS

• GLES2.0 blend shape normal vector weird on OCTAHEDRAL_COMPRESSION, DEVASSERT fail every time #58078
  • observed
    • in Godot: 3.4.2.stable, 3.4.4.stable
    • on: GLES2

iPhone

• GPU artifacts with blend shapes on iPhone (GLES3) #58230
  • observed
    • in Godot: 3.4.2.stable
    • on: iPhone12 mini (15.2) with GLES3

very, very strange

• Blend Shapes visual bug on Linux and video-linux on AMD gpu #41688
  • on GPU: AMD Radeon RX 5600 XT, using video-linux driver, on Manjaro (Linux)

Fixed in Godot 4.x, but still an issue in Godot 3.x

• only one blendshape from multiple mesh instances can apply to a shared resource at a time #54062
  • context: .GLB model which consists of multiple MeshInstances where at least one has blendshapes
  • observed
    • in Godot: 3.3.4.stable
    • on GPU: GeForce 750ti (Windows10)
• blend shape operations on ArrayMesh work incorrectly #31595
  • observed
    • might not be a bug, but an error in usage
    • in Godot: master branch on Aug 23, 2019, so since around Godot 3.2, and still present on Godot 4.0.dev
• Can't Import shape keys animations from Blender using GLTF2 #38443
  • observed
    • in Godot: 3.2.1
    • on: Ubuntu 18.04
  • NOTE: should be indirectly fixed in Godot 4 because of Implement Animation Blend Shape Tracks #53865

Documentation Issues

• When the AnimationTree is enabled, animations with a blend amount of 0 will always be updated by AnimationTree #75179
• There seem to be no way to access Blend Shapes values via code #15778
• Blend shapes are supported in GLES2 godot-docs#5954
• 3.4.4 Shape keys lead to incorrect shading GLES3 #61685
  • observed
    • in Godot: 3.4.4.stable
    • on GPU: NVIDIA RTX 2060, driver 512.95 (Windows10)
  • workaround: By default, glTF exports non-deforming bones for some reason. Exporting only deforming bones resolved this issue (source)
• ArrayMesh.add_surface_from_arrays(...) missing param doc, add_blend_shape(...)  godot-docs#4502

Enhanced Collada Exporter

listing for completeness

• "Triangulate" option not compatible with "Shape-Keys" (morph) animations collada-exporter#69

Related Proposals

• where to save blend shapes
  • Move Blend Shape Modifiers to MeshInstance godot-proposals#2465, or
  • Move blendshapes values to the Mesh resource instead of being in the MeshInstance godot-proposals#3477
  • previously discussed here #37854
• Add an option to apply blendshapes and generate a MeshInstance godot-proposals#24
  • related functionality: SurfaceTool.create_from_blend_shape() (Expose more surface tools and add create_from_blend_shape. #26355)
• blend shapes min/max always -1 to 1 #49249
  • salvageable as proposal
• Creating a trimesh static body from a mesh with blend shapes does not take blend shapes into account #40292
  • not a bug, but an enhancement

[clayjohn]

Commenting here so I don't forget to update documentation later. In 3.x blendshapes could include position, normal, tangents, colors, uvs, and uv2s. In 4.0 blendshapes only apply to position, normal, and tangents.

[fire]

@clayjohn what are your thoughts on adding a default blend shape value to the rendering server?