diff --git a/src/libnest2d/include/libnest2d/optimizers/nlopt/genetic.hpp b/src/libnest2d/include/libnest2d/optimizers/nlopt/genetic.hpp
index 731ead554..b92251ebd 100644
--- a/src/libnest2d/include/libnest2d/optimizers/nlopt/genetic.hpp
+++ b/src/libnest2d/include/libnest2d/optimizers/nlopt/genetic.hpp
@@ -14,6 +14,8 @@ public:
         localmethod_ = m;
         return *this;
     }
+
+    inline void seed(unsigned long val) { nlopt::srand(val); }
 };
 
 template<>
diff --git a/src/libslic3r/SLA/SLASupportTree.cpp b/src/libslic3r/SLA/SLASupportTree.cpp
index cbd27eb7c..4f449523a 100644
--- a/src/libslic3r/SLA/SLASupportTree.cpp
+++ b/src/libslic3r/SLA/SLASupportTree.cpp
@@ -1479,6 +1479,7 @@ public:
                     stc.relative_score_difference = m_cfg.optimizer_rel_score_diff;
                     stc.stop_score = w; // space greater than w is enough
                     GeneticOptimizer solver(stc);
+                    solver.seed(0); // we want deterministic behavior
 
                     auto oresult = solver.optimize_max(
                         [this, pin_r, w, hp](double plr, double azm)
@@ -1778,6 +1779,7 @@ public:
             stc.relative_score_difference = m_cfg.optimizer_rel_score_diff;
             stc.stop_score = 1e6;
             GeneticOptimizer solver(stc);
+            solver.seed(0); // we want deterministic behavior
 
             double r_back = head.r_back_mm;