Respect `up_axis` in Collada (.dae) mesh importer by Abhisheklearn12 · Pull Request #12708 · rerun-io/rerun

Abhisheklearn12 · 2026-03-26T07:45:23Z

What

Read up_axis from document.asset.up_axis in the Collada importer
Compute a correction matrix and pass it as the initial parent_tf to gather_instances_recursive, baking it into every world_from_mesh instance
transform
Z_UP → identity (no correction needed, already matches Rerun's RFU convention)
Y_UP → 90° rotation around X axis (Collada's default, most common case)
X_UP → custom rotation matrix mapping X_UP axes to RFU

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oxkitsune

Thank you!

I think we should handle <child> assets properly as well.

oxkitsune · 2026-03-26T14:50:45Z

-    // TODO(#12335): Respect up_axis from DAE file via ViewCoordinates.
+    // Compute a correction matrix to rotate from the DAE file's coordinate system into Rerun's
+    // default RFU (X=Right, Y=Forward, Z=Up) convention.
+    let correction = match document.asset.up_axis {


Correct me if I'm wrong, but this only applies the correction for the root document's up_axis right?

However COLLADA allows child <asset> metadata to override parent metadata recursively within the child’s scope, from the COLLADA spec:

In the case of hierarchical <asset> elements, where both the parent and child assets supply a value for the same metadata, such as for <unit>, the child asset’s value supersedes the parent’s value within the scope of the child element. This applies recursively.

Thanks! I've updated the PR to handle child elements at both the <visual_scene> and <node> levels, propagating the effective correction recursively to all descendants as per COLLADA spec requires.

Also, as Per the COLLADA spec and the dae-parser library, <asset> can appear at the document, <visual_scene>, and <node> levels, each overriding the parent's value within its scope (Document.asset: Asset, VisualScene.asset: Option<Box<Asset>>, Node.asset: Option<Box<Asset>>)

Abhisheklearn12 · 2026-04-03T06:53:31Z

Fixed in fe64cdb, correction is now applied before composing with parent_tf:

let world_tf = *parent_tf * *correction * Affine3A::from_mat4(local_mat);

Children without their own override get IDENTITY since world_tf is already in RFU.

Abhisheklearn12 · 2026-04-12T06:26:20Z

Hey @oxkitsune , would love your review on my changes when you get a chance. Thanks!

oxkitsune · 2026-04-15T10:08:48Z

Hi @Abhisheklearn12, I pushed a commit.

However since I cannot push LFS artifacts to your fork, please update tests/assets/mesh/box.dae to the following, and update the snapshots:

box.dae

<?xml version="1.0" encoding="utf-8"?>
<COLLADA xmlns="http://www.collada.org/2005/11/COLLADASchema" version="1.4.1">
    <asset>
        <contributor>
            <authoring_tool>modo 801 [Build 77509], Microsoft Windows 7 Service Pack 1 (6.1.7601 Service Pack 1)</authoring_tool>
            <comments>Plug-in: [Build 77509]; Use Absolute Path: No; Merge Reference Items: No; Save Hidden Items: No; Save Cameras: No; Save Lights: No; Save Locators: Yes; Save Triangles as Triangles: Yes; Order Vertex Maps
                Alphabetically: Yes; Bake Matrices: No; Save Vertex Normals: Yes; Save UV Texture Coordinates: Yes; Save Vertex Colors: No; Save Vertex Weights: No; Save Animation: Yes; Sample Animation: No; Sample Animation
                Start: 0; Sample Animation End: 120; Save modo Profile: No; Save Maya Profile: No; Save 3ds Max Profile: No; Formatted Arrays: No;</comments>
            <source_data>file:///C:/Users/Branden/Creative%20Cloud%20Files/03-2015%20Cesium%20Test%20Models/CesiumBoxTest.lxo</source_data>
        </contributor>
        <created>2015-03-04T16:39:37Z</created>
        <modified>2015-03-04T16:39:37Z</modified>
        <up_axis>Y_UP</up_axis>
    </asset>
    <library_materials>
        <material id="Material-Red" name="Red">
            <instance_effect url="#Effect-Red" />
        </material>
    </library_materials>
    <library_effects>
        <effect id="Effect-Red" name="Red">
            <profile_COMMON>
                <technique sid="common">
                    <phong>
                        <diffuse>
                            <color sid="diffuse_effect_rgb">0.8 0 0 1</color>
                        </diffuse>
                        <specular>
                            <color sid="specular_effect_rgb">0.2 0.2 0.2 1</color>
                        </specular>
                        <shininess>
                            <float sid="specular_effect_rgb">256</float>
                        </shininess>
                    </phong>
                </technique>
            </profile_COMMON>
        </effect>
    </library_effects>
    <library_geometries>
        <geometry id="Geometry-mesh002" name="Mesh">
            <mesh>
                <source id="Geometry-mesh002-positions" name="positions">
                    <float_array id="Geometry-mesh002-positions-array" count="24">-0.25 -0.25 -0.25 -0.25 0.25 -0.25 0.25 0.25 -0.25 0.25 -0.25 -0.25 -0.25 -0.25 0.25 -0.25 0.25 0.25 0.25 0.25 0.25 0.25 -0.25 0.25</float_array>
                    <technique_common>
                        <accessor count="8" source="#Geometry-mesh002-positions-array" stride="3">
                            <param name="X" type="float" />
                            <param name="Y" type="float" />
                            <param name="Z" type="float" />
                        </accessor>
                    </technique_common>
                </source>
                <source id="Geometry-mesh002-normals" name="normals">
                    <float_array id="Geometry-mesh002-normals-array" count="18">0 0 1 0 -1 0 1 0 0 0 1 0 -1 0 0 0 0 -1</float_array>
                    <technique_common>
                        <accessor count="6" source="#Geometry-mesh002-normals-array" stride="3">
                            <param name="X" type="float" />
                            <param name="Y" type="float" />
                            <param name="Z" type="float" />
                        </accessor>
                    </technique_common>
                </source>
                <source id="Geometry-mesh002-Texture" name="Texture">
                    <float_array id="Geometry-mesh002-Texture-array" count="28">0.25 1 0.25 0.666667 0.5 1 0.5 0.666667 0 0.666667 0.25 0.333333 0 0.333333 0.5 0.333333 0.75 0.666667 0.75 0.333333 1 0.666667 1 0.333333 0.25 0
                        0.5 0</float_array>
                    <technique_common>
                        <accessor count="14" source="#Geometry-mesh002-Texture-array" stride="2">
                            <param name="S" type="float" />
                            <param name="T" type="float" />
                        </accessor>
                    </technique_common>
                </source>
                <vertices id="Geometry-mesh002-vertices">
                    <input semantic="POSITION" source="#Geometry-mesh002-positions" />
                </vertices>
                <triangles count="12" material="Material-Red">
                    <input semantic="VERTEX" source="#Geometry-mesh002-vertices" offset="0" />
                    <input semantic="NORMAL" source="#Geometry-mesh002-normals" offset="1" />
                    <input semantic="TEXCOORD" source="#Geometry-mesh002-Texture" offset="2" set="0" />
                    <p>4 0 0 7 0 1 5 0 2 6 0 3 5 0 2 7 0 1 7 1 1 4 1 4 3 1 5 0 1 6 3 1 5 4 1 4 6 2 3 7 2 1 2 2 7 3 2 5 2 2 7 7 2 1 5 3 8 6 3 3 1 3 9 2 3 7 1 3 9 6 3 3 4 4 10 5 4 8 0 4 11 1 4 9 0 4 11 5 4 8 0 5 12 1 5 13 3 5 5
                        2 5 7 3 5 5 1 5 13</p>
                </triangles>
            </mesh>
        </geometry>
    </library_geometries>
    <library_visual_scenes>
        <visual_scene id="DefaultScene">
            <node id="Root" name="Root" type="NODE">
                <translate>0 2 0</translate>
                <node id="Geometry-mesh002Node" name="Mesh" type="NODE">
                    <instance_geometry url="#Geometry-mesh002">
                        <bind_material>
                            <technique_common>
                                <instance_material symbol="Material-Red" target="#Material-Red" />
                            </technique_common>
                        </bind_material>
                    </instance_geometry>
                </node>
            </node>
        </visual_scene>
    </library_visual_scenes>
    <scene>
        <instance_visual_scene url="#DefaultScene" />
    </scene>
</COLLADA>

Abhisheklearn12 · 2026-04-15T12:33:59Z

Hi @oxkitsune, I updated tests/assets/mesh/box.dae and regenerated the snapshots.

oxkitsune

LGTM, thanks! I'll get this merged once CI goes green!

Abhisheklearn12 · 2026-04-17T06:39:41Z

hi @oxkitsune, CI’s green, looks good to merge. thanks for the review

oxkitsune · 2026-04-17T07:37:03Z

@rerun-bot reality-sync

rerun-sync · 2026-04-17T07:38:57Z

Sync complete. Mirror PR in reality: https://github.com/rerun-io/reality/pull/1637

Triggered by @oxkitsune

oxkitsune · 2026-04-17T14:07:35Z

@rerun-bot reality-sync

oxkitsune · 2026-04-20T11:26:05Z

@rerun-bot reality-sync

oxkitsune · 2026-04-21T14:32:19Z

hey, there's some internal checks failing. I'll try and fix them tonight 🫡

Abhisheklearn12 · 2026-04-21T14:41:52Z

It's okay @oxkitsune, take your time

oxkitsune · 2026-04-22T12:28:53Z

@rerun-bot reality-sync

### Related - Closes rerun-io#12335 ### What - Read `up_axis` from `document.asset.up_axis` in the Collada importer - Compute a correction matrix and pass it as the initial `parent_tf` to `gather_instances_recursive`, baking it into every `world_from_mesh` instance transform - `Z_UP` → identity (no correction needed, already matches Rerun's RFU convention) - `Y_UP` → 90° rotation around X axis (Collada's default, most common case) - `X_UP` → custom rotation matrix mapping X_UP axes to RFU Source-Ref: 328bfa817a00bf08e25de1185874ac432a7692e9

github-actions Bot reviewed Mar 26, 2026

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oxkitsune self-requested a review March 26, 2026 09:49

oxkitsune requested changes Mar 26, 2026

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Abhisheklearn12 requested a review from oxkitsune March 26, 2026 17:06

oxkitsune added 📺 re_viewer affects re_viewer itself include in changelog labels Mar 30, 2026

oxkitsune requested changes Mar 30, 2026

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Comment thread crates/viewer/re_renderer/src/importer/dae.rs Outdated

Comment thread crates/viewer/re_renderer/src/importer/dae.rs Outdated

Abhisheklearn12 force-pushed the abhisheklearn12/12335-dae-up-axis branch from 372eddd to 5c1ab44 Compare April 3, 2026 06:20

Abhisheklearn12 added 3 commits April 3, 2026 12:10

Respect up_axis in Collada (.dae) mesh importer

b53bdf9

Handle child <asset> up_axis overrides in Collada importer

c0f25be

Fix transform composition for child <asset> up_axis overrides

fe64cdb

Abhisheklearn12 force-pushed the abhisheklearn12/12335-dae-up-axis branch from 5c1ab44 to fe64cdb Compare April 3, 2026 06:41

Abhisheklearn12 requested a review from oxkitsune April 3, 2026 06:48

Abhisheklearn12 and others added 2 commits April 14, 2026 21:21

Merge branch 'main' into abhisheklearn12/12335-dae-up-axis

d9577e9

improve testing setup + fix walking of tree

d253717

Update test asset and snapshots

6d28414

oxkitsune approved these changes Apr 15, 2026

View reviewed changes

fmt

6f60994

Merge branch 'main' into abhisheklearn12/12335-dae-up-axis

d83aace

Abhisheklearn12 added 2 commits April 19, 2026 12:12

Merge branch 'main' into abhisheklearn12/12335-dae-up-axis

c1c77a8

Merge branch 'main' into abhisheklearn12/12335-dae-up-axis

08c9cc0

Merge branch 'main' into abhisheklearn12/12335-dae-up-axis

24abc7f

rerun-sync Bot merged commit a03b2f7 into rerun-io:main Apr 22, 2026
38 of 39 checks passed

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