diff --git a/src/csgops.cc b/src/csgops.cc
index 334db160..98d68c77 100644
--- a/src/csgops.cc
+++ b/src/csgops.cc
@@ -44,11 +44,8 @@ public:
 AbstractNode *CsgModule::evaluate(const Context*, const ModuleInstantiation *inst) const
 {
 	CsgNode *node = new CsgNode(inst, type);
-	foreach (ModuleInstantiation *v, inst->children) {
-		AbstractNode *n = v->evaluate(inst->ctx);
-		if (n != NULL)
-			node->children.push_back(n);
-	}
+	std::vector<AbstractNode *> evaluatednodes = inst->evaluateChildren();
+	node->children.insert(node->children.end(), evaluatednodes.begin(), evaluatednodes.end());
 	return node;
 }