Remove Axes3D archetype and add axis_length to Transform3D (#6676)

### What
- Resolves: #6578

It turns out having a visualizer with no required entities causes all
kinds of problems. This moves us back to only allowing axes if you have
a transform at an entity.

The heuristics are still a bit fancy for backwards compatibility. We
don't use Transform3D as an indicator since that would cause every
transform to get axes by default. Instead, we only create the
Transform3D visualizer if:
- If we have no other visualizers, but otherwise meet the criteria for
Transform3DArrows.
- If someone set an axis_length explicitly, so AxisLengthDetector is
applicable.
  - If we already have the CamerasVisualizer active.

### Shortcomings
- The one big shortcoming still present here is that there's still no
way to use a `default` to force the Transform3D axes to be visible.

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/6676?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/6676?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!

- [PR Build Summary](https://build.rerun.io/pr/6676)
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Author: jleibs

crates/re_space_view_spatial/src/view_3d.rs

@@ -19,7 +19,7 @@ use re_viewer_context::{
     VisualizableEntities, VisualizableFilterContext,
 };
 
-use crate::visualizers::{CamerasVisualizer, Transform3DArrowsVisualizer, Transform3DDetector};
+use crate::visualizers::{AxisLengthDetector, CamerasVisualizer, Transform3DArrowsVisualizer};
 use crate::{
     contexts::register_spatial_contexts,
     heuristics::default_visualized_entities_for_visualizer_kind,
@@ -194,59 +194,67 @@ impl SpaceViewClass for SpatialSpaceView3D {
         visualizable_entities_per_visualizer: &PerVisualizer<VisualizableEntities>,
         indicated_entities_per_visualizer: &PerVisualizer<IndicatedEntities>,
     ) -> SmallVisualizerSet {
-        let applicable_visualizers: HashSet<&ViewSystemIdentifier> =
-            applicable_entities_per_visualizer
-                .iter()
-                .filter_map(|(visualizer, ents)| {
-                    if ents.contains(entity_path) {
-                        Some(visualizer)
-                    } else {
-                        None
-                    }
-                })
-                .collect();
-
-        let available_visualizers: HashSet<&ViewSystemIdentifier> =
-            visualizable_entities_per_visualizer
-                .iter()
-                .filter_map(|(visualizer, ents)| {
-                    if ents.contains(entity_path) {
-                        Some(visualizer)
-                    } else {
-                        None
-                    }
-                })
-                .collect();
+        let arrows_viz = Transform3DArrowsVisualizer::identifier();
+        let axis_detector = AxisLengthDetector::identifier();
+        let camera_viz = CamerasVisualizer::identifier();
 
-        let mut visualizers: SmallVisualizerSet = available_visualizers
+        let applicable: HashSet<&ViewSystemIdentifier> = applicable_entities_per_visualizer
             .iter()
-            .filter_map(|visualizer| {
-                if indicated_entities_per_visualizer
-                    .get(*visualizer)
-                    .map_or(false, |matching_list| matching_list.contains(entity_path))
-                {
-                    Some(**visualizer)
+            .filter_map(|(visualizer, ents)| {
+                if ents.contains(entity_path) {
+                    Some(visualizer)
                 } else {
                     None
                 }
             })
             .collect();
 
-        if available_visualizers.contains(&Transform3DArrowsVisualizer::identifier()) {
-            // There are two cases where we want to activate the [`Transform3DArrowVisualizer`]:
-            //  - If we have no visualizers, but [`Transform3DDetector`] indicates there is a transform here.
-            //  - If we have the [`CamerasVisualizer`] active.
-            if (visualizers.is_empty()
-                && applicable_visualizers.contains(&Transform3DDetector::identifier()))
-                || visualizers.contains(&CamerasVisualizer::identifier())
-            {
-                visualizers.push(Transform3DArrowsVisualizer::identifier());
-            }
-        }
+        let visualizable: HashSet<&ViewSystemIdentifier> = visualizable_entities_per_visualizer
+            .iter()
+            .filter_map(|(visualizer, ents)| {
+                if ents.contains(entity_path) {
+                    Some(visualizer)
+                } else {
+                    None
+                }
+            })
+            .collect();
+
+        // We never want to consider `Transform3DArrows` as directly indicated since it uses the
+        // the Transform3D archetype. This is often used to transform other 3D primitives, where
+        // it might be annoying to always have the arrows show up.
+        let indicated: HashSet<&ViewSystemIdentifier> = indicated_entities_per_visualizer
+            .iter()
+            .filter_map(|(visualizer, ents)| {
+                if visualizer != &arrows_viz && ents.contains(entity_path) {
+                    Some(visualizer)
+                } else {
+                    None
+                }
+            })
+            .collect();
 
-        // If there were no other visualizers, or this is a camera, then we will include axes.
+        // Start with all the entities which are both indicated and visualizable.
+        let mut chosen: SmallVisualizerSet = indicated
+            .intersection(&visualizable)
+            .copied()
+            .copied()
+            .collect();
+
+        // There are three cases where we want to activate the [`Transform3DArrowVisualizer`]:
+        //  - If we have no visualizers, but otherwise meet the criteria for Transform3DArrows.
+        //  - If someone set an axis_length explicitly, so [`AxisLengthDetector`] is applicable.
+        //  - If we already have the [`CamerasVisualizer`] active.
+        if !chosen.contains(&arrows_viz)
+            && visualizable.contains(&arrows_viz)
+            && ((chosen.is_empty() && visualizable.contains(&arrows_viz))
+                || applicable.contains(&axis_detector)
+                || chosen.contains(&camera_viz))
+        {
+            chosen.push(arrows_viz);
+        }
 
-        visualizers
+        chosen
     }
 
     fn spawn_heuristics(

crates/re_space_view_spatial/src/visualizers/mod.rs

@@ -19,7 +19,7 @@ mod transform3d_arrows;
 pub use cameras::CamerasVisualizer;
 pub use images::{ImageVisualizer, ViewerImage};
 pub use spatial_view_visualizer::SpatialViewVisualizerData;
-pub use transform3d_arrows::{add_axis_arrows, Transform3DArrowsVisualizer, Transform3DDetector};
+pub use transform3d_arrows::{add_axis_arrows, AxisLengthDetector, Transform3DArrowsVisualizer};
 
 // ---
 
@@ -69,8 +69,8 @@ pub fn register_2d_spatial_visualizers(
     system_registry.register_visualizer::<meshes::Mesh3DVisualizer>()?;
     system_registry.register_visualizer::<points2d::Points2DVisualizer>()?;
     system_registry.register_visualizer::<points3d::Points3DVisualizer>()?;
+    system_registry.register_visualizer::<transform3d_arrows::AxisLengthDetector>()?;
     system_registry.register_visualizer::<transform3d_arrows::Transform3DArrowsVisualizer>()?;
-    system_registry.register_visualizer::<transform3d_arrows::Transform3DDetector>()?;
     Ok(())
 }
 
@@ -89,8 +89,8 @@ pub fn register_3d_spatial_visualizers(
     system_registry.register_visualizer::<meshes::Mesh3DVisualizer>()?;
     system_registry.register_visualizer::<points2d::Points2DVisualizer>()?;
     system_registry.register_visualizer::<points3d::Points3DVisualizer>()?;
+    system_registry.register_visualizer::<transform3d_arrows::AxisLengthDetector>()?;
     system_registry.register_visualizer::<transform3d_arrows::Transform3DArrowsVisualizer>()?;
-    system_registry.register_visualizer::<transform3d_arrows::Transform3DDetector>()?;
     Ok(())
 }
 

crates/re_space_view_spatial/src/visualizers/transform3d_arrows.rs

@@ -2,8 +2,9 @@ use egui::Color32;
 use re_log_types::{EntityPath, Instance};
 use re_space_view::DataResultQuery;
 use re_types::{
-    archetypes::{Axes3D, Pinhole, Transform3D},
+    archetypes::{Pinhole, Transform3D},
     components::{AxisLength, ImagePlaneDistance},
+    Loggable,
 };
 use re_viewer_context::{
     ApplicableEntities, IdentifiedViewSystem, QueryContext, SpaceViewStateExt,
@@ -37,7 +38,7 @@ impl IdentifiedViewSystem for Transform3DArrowsVisualizer {
 
 impl VisualizerSystem for Transform3DArrowsVisualizer {
     fn visualizer_query_info(&self) -> VisualizerQueryInfo {
-        VisualizerQueryInfo::from_archetype::<Axes3D>()
+        VisualizerQueryInfo::from_archetype::<Transform3D>()
     }
 
     fn filter_visualizable_entities(
@@ -84,8 +85,8 @@ impl VisualizerSystem for Transform3DArrowsVisualizer {
                 world_from_obj,
             );
 
-            let results =
-                data_result.latest_at_with_blueprint_resolved_data::<Axes3D>(ctx, &latest_at_query);
+            let results = data_result
+                .latest_at_with_blueprint_resolved_data::<Transform3D>(ctx, &latest_at_query);
             let axis_length = results.get_mono_with_fallback::<AxisLength>().into();
 
             add_axis_arrows(
@@ -213,22 +214,27 @@ impl TypedComponentFallbackProvider<AxisLength> for Transform3DArrowsVisualizer
 
 re_viewer_context::impl_component_fallback_provider!(Transform3DArrowsVisualizer => [AxisLength]);
 
-/// The `Transform3DDetector` doesn't actually visualize anything, but it allows us to detect
-/// when a transform should otherwise be visualized.
+/// The `AxisLengthDetector` doesn't actually visualize anything, but it allows us to detect
+/// when a transform has set the [`AxisLength`] component.
 ///
 /// See the logic in [`crate::SpatialSpaceView3D`]`::choose_default_visualizers`.
 #[derive(Default)]
-pub struct Transform3DDetector();
+pub struct AxisLengthDetector();
 
-impl IdentifiedViewSystem for Transform3DDetector {
+impl IdentifiedViewSystem for AxisLengthDetector {
     fn identifier() -> re_viewer_context::ViewSystemIdentifier {
-        "Transform3DDetector".into()
+        "AxisLengthDetector".into()
     }
 }
 
-impl VisualizerSystem for Transform3DDetector {
+impl VisualizerSystem for AxisLengthDetector {
     fn visualizer_query_info(&self) -> VisualizerQueryInfo {
-        VisualizerQueryInfo::from_archetype::<Transform3D>()
+        let mut query_info = VisualizerQueryInfo::from_archetype::<Transform3D>();
+
+        query_info.required.insert(AxisLength::name());
+        query_info.indicators = Default::default();
+
+        query_info
     }
 
     fn execute(
@@ -259,4 +265,4 @@ impl VisualizerSystem for Transform3DDetector {
     }
 }
 
-re_viewer_context::impl_component_fallback_provider!(Transform3DDetector => []);
+re_viewer_context::impl_component_fallback_provider!(AxisLengthDetector => []);

crates/re_types/definitions/rerun/archetypes.fbs

@@ -2,7 +2,6 @@ include "./archetypes/annotation_context.fbs";
 include "./archetypes/arrows2d.fbs";
 include "./archetypes/arrows3d.fbs";
 include "./archetypes/asset3d.fbs";
-include "./archetypes/axes3d.fbs";
 include "./archetypes/bar_chart.fbs";
 include "./archetypes/boxes2d.fbs";
 include "./archetypes/boxes3d.fbs";

crates/re_types/definitions/rerun/archetypes/axes3d.fbs

@@ -16,4 +16,12 @@ table Transform3D (
 ) {
   /// The transform
   transform: rerun.components.Transform3D ("attr.rerun.component_required", order: 1000);
+
+  // --- Optional ---
+
+  /// Visual length of the 3 axes.
+  ///
+  /// The length is interpreted in the local coordinate system of the transform.
+  /// If the transform is scaled, the axes will be scaled accordingly.
+  axis_length: rerun.components.AxisLength ("attr.rerun.component_optional", nullable, order: 2000);
 }