diff --git a/python/_util.py b/python/_util.py
index f03a565dc..40d4db571 100644
--- a/python/_util.py
+++ b/python/_util.py
@@ -223,6 +223,24 @@ def load_module(name, path, persist=True):
     re.VERBOSE | re.IGNORECASE,
 )
 
+_UNVERSIONED_MODEL_PATTERN = (
+    r"""
+    (?P<model_name>
+        (?:
+            [a-zA-Z0-9]+
+        )
+        |
+        (?:
+            (?:[a-zA-Z0-9]+(?:[-_\.][a-zA-Z0-9]+)*(?:[-_\.][a-zA-Z]+[a-zA-Z0-9]*))?
+        )
+    )
+    (?:
+        -
+        (?P<version>"""
+    + _VERSION_PATTERN
+    + r"))?"
+)
+
 _MODEL_PATTERN = (
     r"""
     (?P<model_name>
@@ -418,128 +436,123 @@ def tokenize_version(version):
     return tuple(token_list)
 
 
-def _get_model_path(model_name, prefix=None, suffix=None, is_file=True, must_exist=True):
-    # Get the path to the model file
-    _model_regex = re.compile(
-        r"^\s*" + _MODEL_PATTERN + ("" if suffix is None else r"(?:" + suffix + r")?") + r"\s*$",
-        re.VERBOSE | re.IGNORECASE,
-    )
-    if suffix is None:
-        suffix = ""
-    # Get the path to the resources directory
-    resources_dir = resource_package_dir()
+def _get_base_directory(resources_dir, prefix):
     base_dir = resources_dir
-
-    # Add prefix if present
     if prefix is not None:
         base_dir = os.path.join(base_dir, prefix)
+    return base_dir
 
-    # Get the model name and version
-    d = _model_regex.match(model_name)
-    if d is None:
-        raise ValueError("Invalid model name: {}".format(model_name))
-    d = d.groupdict()
-    model_name = d["model_name"]
-    version = d["version"]
-
-    # Search for the model folder in the resources directory
+def _find_model_folder_and_file(base_dir, model_name, must_exist, specific_file=None):
     model_names = [
         f for f in os.listdir(base_dir) if not os.path.isfile(os.path.join(base_dir, f))
     ]
-    model_names = [f for f in model_names if f.lower().startswith(model_name.lower())]
 
-    folder_exists = False
+    exact_model_names = [f for f in model_names if f.lower() == model_name.lower()]
+
+    if len(exact_model_names) == 0:
+        model_names = [f for f in model_names if f.lower().startswith(model_name.lower())]
+    else:
+        model_names = exact_model_names
 
     if len(model_names) == 0 and must_exist:
-        # Whoops, we didn't find the model folder!
-        raise ValueError(
-            "No model folders found for {}\nSearched in ".format(model_name, base_dir)
-        )
+        raise ValueError(f"No model folders found for {model_name}\nSearched in {base_dir}")
     elif len(model_names) == 0 and not must_exist:
-        # Let's use the provided model name as the folder name
-        model_name = model_name
+        return model_name, False, None
     elif len(model_names) == 1:
-        # We found the model folder!
-        folder_exists = True
-        model_name = model_names[0]
+        name = model_names[0]
+        if specific_file is not None:
+            specific_file_path = os.path.join(base_dir, name, specific_file)
+            if os.path.isfile(specific_file_path):
+                return name, True, specific_file_path
+        else:
+            return name, True, None
     else:
-        # Multiple model folders found, we cannot decide which one to use
-        raise ValueError(
-            "Multiple directories found for {}\nSearched in ".format(
-                model_name, base_dir
-            )
-        )
+        raise ValueError(f"Multiple directories found for {model_name}\nSearched in {base_dir}")
 
+def _get_model_files(base_dir, model_name, is_file, folder_exists, version=None):
     if folder_exists:
-        # Search for the model file in the model folder
-        model_files = [
-            f
-            for f in os.listdir(os.path.join(base_dir, model_name))
+        if version:
+            version_dir = os.path.join(base_dir, model_name, f"v{version}")
+            if os.path.isdir(version_dir):
+                return [
+                    f for f in os.listdir(version_dir)
+                    if is_file == os.path.isfile(os.path.join(version_dir, f))
+                ]
+        return [
+            f for f in os.listdir(os.path.join(base_dir, model_name))
             if is_file == os.path.isfile(os.path.join(base_dir, model_name, f))
         ]
-    else:
-        model_files = []
+    return []
 
-    # From the found model files, extract the model versions
+def _extract_model_versions(model_files, model_regex, model_name):
     model_versions = []
     for f in model_files:
-        d = _model_regex.match(f)
+        d = model_regex.match(f)
         if d is not None:
             if d.groupdict()["version"] is not None:
                 model_versions.append(normalize_version(d.groupdict()["version"]))
             else:
-                print(ValueError(
-                    "Input model file has no version: {}\nSearched in ".format(
-                        f, os.path.join(base_dir, model_name)
-                    )
-                ))
+                print(f"Warning: Input model file has no version: {f}")
         elif f.lower().startswith(model_name.lower()):
-            print(ValueError(
-                "Unable to parse version from {}\nFound in ".format(
-                    f, os.path.join(base_dir, model_name)
-                )
-            ))
-
-    # Raise an error if no model file is found and we require it to exist
-    if len(model_versions) == 0 and must_exist:
-        raise ValueError(
-            "No model found for {}\nSearched in {}".format(
-                model_name, os.path.join(base_dir, model_name)
-            )
-        )
+            print(f"Warning: Unable to parse version from {f}")
+    return model_versions
 
+def _get_model_file_name(version, model_versions, model_files, model_name, suffix, must_exist):
     if version is None and must_exist:
-        # If no version is provided, use the latest version
-        version_idx, version = max(
-            enumerate(model_versions), key=lambda x: tokenize_version(x[1])
-        )
-        model_file_name = model_files[version_idx]
+        version_idx, version = max(enumerate(model_versions), key=lambda x: tokenize_version(x[1]))
+        return model_files[version_idx]
     elif version is None and not must_exist:
-        # If no version is provided and we don't require it to exist, default to v1
         version = "v1"
-        model_file_name = "{}-v{}{}".format(model_name, version, suffix)
+        return f"{model_name}-v{version}{suffix}"
     else:
-        # A version is provided
         version = normalize_version(version)
         if must_exist:
-            # If the version must exist, raise an error if it doesn't
             if version not in model_versions:
-                raise ValueError(
-                    "No model found for {}-{}\nSearched in ".format(
-                        model_name, version, os.path.join(base_dir, model_name)
-                    )
-                )
+                raise ValueError(f"No model found for {model_name}-{version}")
             version_idx = model_versions.index(version)
-            model_file_name = model_files[version_idx]
+            return model_files[version_idx]
         else:
-            # The version doesn't have to exist
             if version in model_versions:
-                # If the version exists, use it
                 version_idx = model_versions.index(version)
-                model_file_name = model_files[version_idx]
+                return model_files[version_idx]
             else:
-                # Otherwise use the provided version
-                model_file_name = "{}-v{}{}".format(model_name, version, suffix)
+                return f"{model_name}-v{version}{suffix}"
+
+def _get_model_path(model_name, prefix=None, suffix=None, is_file=True, must_exist=True, specific_file=None):
+    _model_regex = re.compile(
+        r"^\s*" + _MODEL_PATTERN + ("" if suffix is None else r"(?:" + suffix + r")?") + r"\s*$",
+        re.VERBOSE | re.IGNORECASE,
+    )
+    suffix = "" if suffix is None else suffix
+
+    resources_dir = resource_package_dir()
+    base_dir = _get_base_directory(resources_dir, prefix)
+
+    d = _model_regex.match(model_name)
+    if d is None:
+        raise ValueError(f"Invalid model name: {model_name}")
+    d = d.groupdict()
+    model_name, version = d["model_name"], d["version"]
+
+    model_name, folder_exists, specific_file_path = _find_model_folder_and_file(base_dir, model_name, must_exist, specific_file)
+
+    if specific_file_path and not version:
+        return os.path.dirname(specific_file_path)
+
+    model_files = _get_model_files(base_dir, model_name, is_file, folder_exists, version)
+    model_versions = _extract_model_versions(model_files, _model_regex, model_name)
+
+    if len(model_versions) == 0 and must_exist:
+        if specific_file_path:
+            return os.path.dirname(specific_file_path)
+        raise ValueError(f"No model found for {model_name}\nSearched in {os.path.join(base_dir, model_name)}")
+
+    model_file_name = _get_model_file_name(version, model_versions, model_files, model_name, suffix, must_exist)
+
+    if version:
+        version_dir = os.path.join(base_dir, model_name, f"v{version}")
+        if os.path.isdir(version_dir):
+            return os.path.join(version_dir, model_file_name)
 
     return os.path.join(base_dir, model_name, model_file_name)
 
@@ -560,26 +573,28 @@ def get_material_model_file_path(model_name, must_exist=True):
 
 
 def get_flux_model_path(model_name, must_exist=True):
-    return _get_model_path(model_name, prefix=_resource_folder_by_name["flux"], is_file=False, must_exist=must_exist)
+    return _get_model_path(model_name, prefix=_resource_folder_by_name["flux"], is_file=False, must_exist=must_exist, specific_file=f"flux.py")
 
 
 def get_detector_model_path(model_name, must_exist=True):
-    return _get_model_path(model_name, prefix=_resource_folder_by_name["detector"], is_file=False, must_exist=must_exist)
+    return _get_model_path(model_name, prefix=_resource_folder_by_name["detector"], is_file=False, must_exist=must_exist, specific_file=f"detector.py")
 
 
 def get_processes_model_path(model_name, must_exist=True):
-    return _get_model_path(model_name, prefix=_resource_folder_by_name["processes"], is_file=False, must_exist=must_exist)
+    return _get_model_path(model_name, prefix=_resource_folder_by_name["processes"], is_file=False, must_exist=must_exist, specific_file="processes.py")
 
 
 def load_resource(resource_type, resource_name, *args, **kwargs):
     folder = _resource_folder_by_name[resource_type]
+    specific_file = f"{resource_type}.py"
 
-    abs_dir = _get_model_path(resource_name, prefix=folder, is_file=False, must_exist=True)
+    abs_dir = _get_model_path(resource_name, prefix=folder, is_file=False, must_exist=True, specific_file=specific_file)
 
-    fname = os.path.join(abs_dir, f"{resource_name}.py")
+    fname = os.path.join(abs_dir, f"{resource_type}.py")
+    print(fname)
     assert(os.path.isfile(fname))
     resource_module = load_module(f"siren-{resource_type}-{resource_name}", fname, persist=False)
-    loader = getattr(resource_module, f"load_{resource_name}")
+    loader = getattr(resource_module, f"load_{resource_type}")
     resource = loader(*args, **kwargs)
     return resource