diff --git a/examples/dminer/src/dminer/core/chunk.d b/examples/dminer/src/dminer/core/chunk.d
index 70837494..fc737b3d 100644
--- a/examples/dminer/src/dminer/core/chunk.d
+++ b/examples/dminer/src/dminer/core/chunk.d
@@ -6,7 +6,7 @@ import dminer.core.world;
 import dlangui.graphics.scene.mesh;
 
 
-//version = FAST_VISIBILITY_PATH;
+version = FAST_VISIBILITY_PATH;
 
 // Y range: 0..CHUNK_DY-1
 immutable int CHUNK_DY = 128;
@@ -1529,6 +1529,7 @@ struct VisibilityCheckIterator {
     Vector3d camPos;
     SmallChunk * startChunk;
     ChunkVisitor visitor;
+    int maxHeight;
     int maxDistance;
     int maxDistanceSquared;
     VisibilityCheckChunk[] plannedChunks;
@@ -1549,17 +1550,19 @@ struct VisibilityCheckIterator {
         // mask test
         if (!mask)
             return;
+        if (p.y > maxHeight + 16 && p.y > startPos.y)
+            return;
         // distance test
         Vector3d diff = (p + Vector3d(4,4,4)) - camPos;
         if (diff.squaredLength() > maxDistanceSquared)
             return;
         int distance = diff.squaredLength;
-        if (distance > 10*10) {
+        if (distance > 16*16) {
             diff = (diff * 256 + cameraDirection * 16) / 256;
             //diff += cameraDirection;
             // direction test (TODO)
             int dot = diff.dot(cameraDirection);
-            if (dot < 12000)
+            if (dot < 8000)
                 return;
         }
         //....
@@ -1619,6 +1622,9 @@ struct VisibilityCheckIterator {
         visitedChunks.length = 0;
         maxDistanceSquared = maxDistance * maxDistance;
         this.maxDistance = maxDistance;
+        maxHeight = world.regionHeight(startPos.x, startPos.z, maxDistance + 8) & 0xFFFFFF8 + 7;
+        import dlangui.core.logger;
+        Log.d("startPos: ", startPos, "  maxHeight:", maxHeight);
     }
     Vector3d cameraDirection;
     void visitVisibleChunks(ChunkVisitor visitor, Vector3d cameraDirection) {
diff --git a/examples/dminer/src/dminer/core/world.d b/examples/dminer/src/dminer/core/world.d
index a2fcde70..46234007 100644
--- a/examples/dminer/src/dminer/core/world.d
+++ b/examples/dminer/src/dminer/core/world.d
@@ -178,7 +178,7 @@ class World {
     /// get max Y position of non-empty cell in region (x +- size, z +- size)
     int regionHeight(int x, int z, int size) {
         int top = -1;
-        int delta = size / 8 + 1;
+        int delta = size + 1;
         for (int dx = x - delta; dx <= x + delta; dx += 8) {
             for (int dz = z - delta; dz <= z + delta; dz += 8) {
                 if (ChunkStack * stack = getCellChunkStack(x, z)) {
diff --git a/examples/dminer/src/minermain.d b/examples/dminer/src/minermain.d
index 88b56348..ccd282b6 100644
--- a/examples/dminer/src/minermain.d
+++ b/examples/dminer/src/minermain.d
@@ -132,9 +132,9 @@ class MinerDrawable : MaterialDrawableObject, ChunkVisitor {
             float camDist = (_camPosition - chunkPos).length;
             vec3 chunkDirection = (chunkPos - (_camPosition - (_camForwardVector * 12))).normalized;
             float dot = _camForwardVector.dot(chunkDirection);
-            float threshold = 0.87;
-            if (camDist < 12)
-                threshold = 0.5;
+            float threshold = 0.80;
+            if (camDist < 16)
+                threshold = 0.2;
             //Log.d("visit() chunkPos ", chunkPos, " chunkDir ", chunkDirection, " camDir ", " dot ", dot, " threshold ", threshold);
 
             if (dot < threshold) { // cos(45)