diff --git a/crates/spirv_backend/src/adapt.rs b/crates/spirv_backend/src/adapt.rs
index 108c15d..b3c5033 100644
--- a/crates/spirv_backend/src/adapt.rs
+++ b/crates/spirv_backend/src/adapt.rs
@@ -1,4 +1,4 @@
-use crate::sim::{StepEContext, StepHContext, VolumeSampleNeg, VolumeSamplePos};
+use coremem_types::step::{StepEContext, StepHContext, VolumeSampleNeg, VolumeSamplePos};
 use crate::support::{Array3, Array3Mut, UnsizedArray};
 use coremem_types::compound::Optional;
 use coremem_types::mat::Material;
diff --git a/crates/spirv_backend/src/lib.rs b/crates/spirv_backend/src/lib.rs
index 1e42b7e..37e64ec 100644
--- a/crates/spirv_backend/src/lib.rs
+++ b/crates/spirv_backend/src/lib.rs
@@ -13,7 +13,6 @@ pub use spirv_std::glam;
 use spirv_std::macros::spirv;
 
 mod adapt;
-pub mod sim;
 pub mod support;
 
 pub use adapt::SerializedSimMeta;
diff --git a/crates/types/src/lib.rs b/crates/types/src/lib.rs
index b4a4402..74ee7b6 100644
--- a/crates/types/src/lib.rs
+++ b/crates/types/src/lib.rs
@@ -4,6 +4,7 @@
 pub mod compound;
 pub mod mat;
 pub mod real;
+pub mod step;
 pub mod vec;
 // private because `vec` re-exports to important vecu constructs
 mod vecu;
diff --git a/crates/spirv_backend/src/sim.rs b/crates/types/src/step.rs
similarity index 97%
rename from crates/spirv_backend/src/sim.rs
rename to crates/types/src/step.rs
index e918e47..8b34d16 100644
--- a/crates/spirv_backend/src/sim.rs
+++ b/crates/types/src/step.rs
@@ -1,8 +1,7 @@
-// use spirv_std::RuntimeArray;
-use coremem_types::compound::Optional;
-use coremem_types::mat::Material;
-use coremem_types::real::Real;
-use coremem_types::vec::Vec3;
+use crate::compound::Optional;
+use crate::mat::Material;
+use crate::real::Real;
+use crate::vec::Vec3;
 
 /// Package the field vectors adjacent to some particular location.
 /// Particular those at negative offsets from the midpoint.