diff --git a/src/main/scala/com/databricks/labs/mosaic/expressions/geometry/ST_Triangulate.scala b/src/main/scala/com/databricks/labs/mosaic/expressions/geometry/ST_Triangulate.scala
index 39f384bd4..a5c873d83 100644
--- a/src/main/scala/com/databricks/labs/mosaic/expressions/geometry/ST_Triangulate.scala
+++ b/src/main/scala/com/databricks/labs/mosaic/expressions/geometry/ST_Triangulate.scala
@@ -5,6 +5,7 @@ import com.databricks.labs.mosaic.core.geometry.api.GeometryAPI
 import com.databricks.labs.mosaic.core.geometry.linestring.MosaicLineString
 import com.databricks.labs.mosaic.core.geometry.multilinestring.MosaicMultiLineString
 import com.databricks.labs.mosaic.core.geometry.multipoint.MosaicMultiPoint
+import com.databricks.labs.mosaic.core.geometry.point.MosaicPoint
 import com.databricks.labs.mosaic.core.types.model.GeometryTypeEnum.{MULTIPOINT, POINT}
 import com.databricks.labs.mosaic.expressions.base.{GenericExpressionFactory, WithExpressionInfo}
 import com.databricks.labs.mosaic.expressions.geometry.base.VectorExpression
@@ -49,10 +50,29 @@ case class ST_Triangulate (
                 .eval(input)
                 .asInstanceOf[ArrayData]
                 .toObjectArray(firstElementType)
-                .map(geometryAPI.geometry(_, firstElementType))
+                .map({
+                    obj =>
+                        val g = geometryAPI.geometry(obj, firstElementType)
+                        g.getGeometryType.toUpperCase(Locale.ROOT) match {
+                            case "POINT" => g.asInstanceOf[MosaicPoint]
+                            case _ => throw new UnsupportedOperationException("ST_Triangulate requires Point geometry as masspoints input")
+                        }
+                })
 
         val multiPointGeom = geometryAPI.fromSeq(pointsGeom, MULTIPOINT).asInstanceOf[MosaicMultiPoint]
-        val linesGeom = inputLinesArray.eval(input).asInstanceOf[ArrayData].toObjectArray(secondElementType).map(geometryAPI.geometry(_, secondElementType).asInstanceOf[MosaicLineString])
+        val linesGeom =
+            inputLinesArray
+                .eval(input)
+                .asInstanceOf[ArrayData]
+                .toObjectArray(secondElementType)
+                .map({
+                    obj =>
+                        val g = geometryAPI.geometry(obj, secondElementType)
+                            g.getGeometryType.toUpperCase(Locale.ROOT) match {
+                                case "LINESTRING" => g.asInstanceOf[MosaicLineString]
+                                case _ => throw new UnsupportedOperationException("ST_Triangulate requires LINESTRING geometry as breakline input")
+                            }
+                })
 
         val triangles =  multiPointGeom.triangulate(linesGeom, inputTolerance.eval(input).asInstanceOf[Double])
 
diff --git a/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateBehaviours.scala b/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateBehaviours.scala
index 1a2108a8f..21d53c27f 100644
--- a/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateBehaviours.scala
+++ b/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateBehaviours.scala
@@ -34,4 +34,30 @@ trait ST_TriangulateBehaviours extends QueryTest {
 
     }
 
+    def conformingTriangulateBehavior(indexSystem: IndexSystem, geometryAPI: GeometryAPI): Unit = {
+
+        val mc = mosaicContext
+        import mc.functions._
+        val sc = spark
+        import sc.implicits._
+        mc.register(spark)
+
+        val pointsPath = "src/test/resources/binary/elevation/sd46_dtm_point.shp"
+        val linesPath = "src/test/resources/binary/elevation/sd46_dtm_breakline.shp"
+        val points = MosaicContext.read.option("asWKB", "true").format("multi_read_ogr").load(pointsPath)
+        val breaklines = MosaicContext.read.option("asWKB", "true").format("multi_read_ogr").load(linesPath)
+        val linesDf = breaklines
+            .where(st_geometrytype($"geom_0") === "LINESTRING")
+            .groupBy()
+            .agg(collect_list($"geom_0").as("breaklines"))
+        val result = points
+            .groupBy()
+            .agg(collect_list($"geom_0").as("masspoints"))
+            .crossJoin(linesDf)
+            .withColumn("mesh", st_triangulate($"masspoints", $"breaklines", lit(0.01)))
+            .drop($"masspoints", $"breaklines")
+        noException should be thrownBy result.collect()
+
+    }
+
 }
diff --git a/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateTest.scala b/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateTest.scala
index ec5f2e1e3..797a787cd 100644
--- a/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateTest.scala
+++ b/src/test/scala/com/databricks/labs/mosaic/expressions/geometry/ST_TriangulateTest.scala
@@ -7,5 +7,6 @@ import org.apache.spark.sql.test.SharedSparkSession
 
 class ST_TriangulateTest extends QueryTest with SharedSparkSession with ST_TriangulateBehaviours {
     test("Testing ST_Triangulate (H3, JTS) to produce unconstrained triangulation") { simpleTriangulateBehavior(H3IndexSystem, JTS)}
+    test("Testing ST_Triangulate (H3, JTS) to produce conforming triangulation") { conformingTriangulateBehavior(H3IndexSystem, JTS)}
 
 }