Fix transform3d_simple and reenable roundtrip test

docs/code-examples/roundtrips.py

@@ -52,10 +52,6 @@
     "point3d_random": ["cpp", "py", "rust"], # TODO(#3206): need to align everything to use PCG64 in the same order etc... don't have time for that.
     "tensor_one_dim": ["cpp", "py", "rust"], # TODO(#3206): need to align everything to use PCG64 in the same order etc... don't have time for that.
     "tensor_simple": ["cpp", "py", "rust"], # TODO(#3206): need to align everything to use PCG64 in the same order etc... don't have time for that.
-    # TODO(#3207): two issues:
-    #   - cpp sends an identity transform for no reason
-    #   - python has a crazy indicator component out of nowhere
-    "transform3d_simple": ["cpp", "py", "rust"],
 }
 
 # fmt: on

docs/code-examples/transform3d_simple.py

@@ -7,14 +7,10 @@
 
 rr.init("rerun_example_transform3d", spawn=True)
 
-origin = [0, 0, 0]
-base_vector = [0, 1, 0]
+rr2.log("base", rr2.Arrows3D([0, 1, 0]))
 
-rr.log_arrow("base", origin=origin, vector=base_vector)
-
-rr2.log("base/translated", rrd.TranslationRotationScale3D(translation=[1, 0, 0]))
-
-rr.log_arrow("base/translated", origin=origin, vector=base_vector)
+rr2.log("base/translated", rrd.TranslationAndMat3x3(translation=[1, 0, 0]))
+rr2.log("base/translated", rr2.Arrows3D([0, 1, 0]))
 
 rr2.log(
     "base/rotated_scaled",
@@ -23,5 +19,4 @@
         scale=2,
     ),
 )
-
-rr.log_arrow("base/rotated_scaled", origin=origin, vector=base_vector)
+rr2.log("base/rotated_scaled", rr2.Arrows3D([0, 1, 0]))

docs/code-examples/transform3d_simple.rs

@@ -3,7 +3,7 @@
 use rerun::{
     archetypes::{Arrows3D, Transform3D},
     datatypes::{
-        Angle, Mat3x3, RotationAxisAngle, Scale3D, TranslationAndMat3x3, TranslationRotationScale3D,
+        Angle, RotationAxisAngle, Scale3D, TranslationAndMat3x3, TranslationRotationScale3D,
     },
     RecordingStreamBuilder,
 };
@@ -16,7 +16,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     rec.log(
         "base/translated",
-        &Transform3D::new(TranslationAndMat3x3::new([1.0, 0.0, 0.0], Mat3x3::IDENTITY)),
+        &Transform3D::new(TranslationAndMat3x3::translation([1.0, 0.0, 0.0])),
     )?;
 
     rec.log("base/translated", &Arrows3D::new([(0.0, 1.0, 0.0)]))?;