fix: #34051 Collada export crashes

diff --git a/source/blender/collada/ControllerExporter.cpp b/source/blender/collada/ControllerExporter.cpp
index c8307589af4e252c1e3b2e9e8d85fb7d94fef117..570473466171605417ae740ba719154d397babde 100644 (file)
--- a/source/blender/collada/ControllerExporter.cpp
+++ b/source/blender/collada/ControllerExporter.cpp
@@ -246,10 +246,13 @@ void ControllerExporter::export_skin_controller(Object *ob, Object *ob_arm)
                        float sumw = 0.0f;
 
                        for (j = 0; j < vert->totweight; j++) {
-                               int joint_index = joint_index_by_def_index[vert->dw[j].def_nr];
-                               if (joint_index != -1 && vert->dw[j].weight > 0.0f) {
-                                       jw[joint_index] += vert->dw[j].weight;
-                                       sumw += vert->dw[j].weight;
+                               int idx = vert->dw[j].def_nr;
+                               if (idx >= 0) {
+                                       int joint_index = joint_index_by_def_index[idx];
+                                       if (joint_index != -1 && vert->dw[j].weight > 0.0f) {
+                                               jw[joint_index] += vert->dw[j].weight;
+                                               sumw += vert->dw[j].weight;
+                                       }
                                }
                        }