diff --git a/doc/source/api_ref/cfaces.rst b/doc/source/api_ref/core/cfaces.rst
similarity index 100%
rename from doc/source/api_ref/cfaces.rst
rename to doc/source/api_ref/core/cfaces.rst
diff --git a/doc/source/api_ref/cfields.rst b/doc/source/api_ref/core/cfields.rst
similarity index 100%
rename from doc/source/api_ref/cfields.rst
rename to doc/source/api_ref/core/cfields.rst
diff --git a/doc/source/api_ref/cmaterials.rst b/doc/source/api_ref/core/cmaterials.rst
similarity index 100%
rename from doc/source/api_ref/cmaterials.rst
rename to doc/source/api_ref/core/cmaterials.rst
diff --git a/doc/source/api_ref/ctracer.rst b/doc/source/api_ref/core/ctracer.rst
similarity index 100%
rename from doc/source/api_ref/ctracer.rst
rename to doc/source/api_ref/core/ctracer.rst
diff --git a/doc/source/api_ref/tracer.rst b/doc/source/api_ref/core/tracer.rst
similarity index 100%
rename from doc/source/api_ref/tracer.rst
rename to doc/source/api_ref/core/tracer.rst