Geometry Nodes: new Trim String node

This adds a new Trim String node. It removes specific characters at the
beginning and end of a string. Most often this is used to remove unnecessary
whitespace but it can be used with other characters too.

Since it's the most common use-case, and it's tricky to type in manually, there
is a special "Whitespace" option on the node which includes spaces, newlines,
tabs and carriage-return (` \t\n\r`).

I originally used this while working on the physics system to "fix" tag names
provided by the user in a comma-separated-list.

Pull Request: https://projects.blender.org/blender/blender/pulls/154465

scripts/startup/bl_ui/node_add_menu_geometry.py

@@ -660,6 +660,7 @@ class NODE_MT_gn_utilities_text_base(node_add_menu.NodeMenu):
         self.node_operator(layout, "FunctionNodeSliceString")
         if context.preferences.experimental.use_geometry_nodes_lists:
             self.node_operator(layout, "FunctionNodeSplitString")
+        self.node_operator(layout, "FunctionNodeTrimString")
         layout.separator()
         self.node_operator(layout, "FunctionNodeFindInString")
         self.node_operator(layout, "FunctionNodeStringLength")

source/blender/makesrna/intern/rna_nodetree.cc

@@ -10342,6 +10342,7 @@ static void rna_def_nodes(BlenderRNA *brna)
   define("FunctionNode", "FunctionNodeTransformDirection");
   define("FunctionNode", "FunctionNodeTransformPoint");
   define("FunctionNode", "FunctionNodeTransposeMatrix");
+  define("FunctionNode", "FunctionNodeTrimString");
   define("FunctionNode", "FunctionNodeValueToString");
 
   define("GeometryNode", "GeometryNodeAccumulateField");

source/blender/nodes/function/CMakeLists.txt

@@ -69,6 +69,7 @@ set(SRC
   nodes/node_fn_transform_direction.cc
   nodes/node_fn_transform_point.cc
   nodes/node_fn_transpose_matrix.cc
+  nodes/node_fn_trim_string.cc
   nodes/node_fn_value_to_string.cc
 
   node_function_util.cc

source/blender/nodes/function/nodes/node_fn_trim_string.cc

@@ -0,0 +1,79 @@
+/* SPDX-FileCopyrightText: 2026 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "node_function_util.hh"
+
+namespace blender::nodes::node_fn_trim_string_cc {
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.is_function_node();
+  b.use_custom_socket_order();
+  b.allow_any_socket_order();
+  b.add_input<decl::String>("String").optional_label();
+  b.add_output<decl::String>("String").align_with_previous();
+  b.add_input<decl::String>("Characters")
+      .optional_label()
+      .description("Individual characters to trim. The order of characters does not matter");
+  b.add_input<decl::Bool>("Whitespace")
+      .default_value(true)
+      .description("Trim whitespace characters in addition to the provided characters");
+  {
+    auto &p = b.add_panel("Limit"_ustr).default_closed(true);
+    p.add_input<decl::Bool>("Start").default_value(true).description(
+        "Trim the beginning of the string");
+    p.add_input<decl::Bool>("End").default_value(true).description(
+        "Trim at the end of the string");
+  }
+}
+
+static void node_build_multi_function(NodeMultiFunctionBuilder &builder)
+{
+  static auto trim_fn = mf::build::SI5_SO<std::string, std::string, bool, bool, bool, std::string>(
+      "Trim",
+      [](const std::string &input_str,
+         const std::string &characters,
+         const bool trim_whitespace,
+         const bool trim_start,
+         const bool trim_end) {
+        std::string characters_to_trim = characters;
+        if (trim_whitespace) {
+          characters_to_trim.append(" \t\n\r");
+        }
+        StringRef str = input_str;
+        int64_t start = 0;
+        int64_t end = str.size();
+        if (trim_start) {
+          const int64_t i = str.find_first_not_of(characters_to_trim);
+          if (i != StringRef::not_found) {
+            start = i;
+          }
+        }
+        if (trim_end) {
+          const int64_t i = str.find_last_not_of(characters_to_trim);
+          if (i != StringRef::not_found) {
+            end = i + 1;
+          }
+        }
+        std::string result = str.substr(start, end - start);
+        return result;
+      });
+  builder.set_matching_fn(&trim_fn);
+}
+
+static void node_register()
+{
+  static bke::bNodeType ntype;
+
+  fn_node_type_base(&ntype, "FunctionNodeTrimString");
+  ntype.ui_name = "Trim String";
+  ntype.ui_description = "Remove characters from the beginning and end of a string";
+  ntype.nclass = NODE_CLASS_CONVERTER;
+  ntype.declare = node_declare;
+  ntype.build_multi_function = node_build_multi_function;
+  bke::node_register_type(ntype);
+}
+NOD_REGISTER_NODE(node_register)
+
+}  // namespace blender::nodes::node_fn_trim_string_cc

tests/files/modeling/geometry_nodes/utilities/trim_string.blend

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:7e43ffeb6150b0ce2e2ed6711dfe87527408d021901ff683620e6c14a1820ef6
+size 101062