diff --git a/common/bspfile.cc b/common/bspfile.cc
index 9fa1bcea..7aec366a 100644
--- a/common/bspfile.cc
+++ b/common/bspfile.cc
@@ -586,6 +586,11 @@ public:
         auto bits_a = contentflags_to_bits(contents0);
         auto bits_b = contentflags_to_bits(contents1);
 
+        // can't see through solid
+        if (bits_a.solid || bits_b.solid) {
+            return false;
+        }
+
         bool a_translucent = transwater ? (bits_a.water || bits_a.slime || bits_a.lava) : false;
         bool b_translucent = transwater ? (bits_b.water || bits_b.slime || bits_b.lava) : false;
 
@@ -597,9 +602,6 @@ public:
         if (bits_b.detail || b_translucent)
             bits_b = q1_contentflags_bits();
 
-        if (bits_a.solid || bits_b.solid)
-            return false; // can't see through solid
-
         if ((bits_a ^ bits_b).all_empty())
             return true; // identical on both sides
 
diff --git a/qbsp/prtfile.cc b/qbsp/prtfile.cc
index 982b9065..f3595f5c 100644
--- a/qbsp/prtfile.cc
+++ b/qbsp/prtfile.cc
@@ -73,8 +73,14 @@ static void WritePortals_r(node_t *node, std::ofstream &portalFile, bool cluster
         front = clusters ? p->nodes[0]->viscluster : p->nodes[0]->visleafnum;
         back = clusters ? p->nodes[1]->viscluster : p->nodes[1]->visleafnum;
 
-        Q_assert(front != -1);
-        Q_assert(back != -1);
+        if (front == -1 || back == -1) {
+            auto front_contents = ClusterContents(p->nodes.front);
+            auto back_contents = ClusterContents(p->nodes.back);
+
+            FError("front {}, cluster contents: {}. back {}, cluster contents: {}. portal: {}", front,
+                front_contents.to_string(qbsp_options.target_game), back,
+                back_contents.to_string(qbsp_options.target_game), w->center());
+        }
 
         /*
          * sometimes planes get turned around when they are very near the
diff --git a/testmaps/q1_detail_touching_water.map b/testmaps/q1_detail_touching_water.map
new file mode 100644
index 00000000..bcff7046
--- /dev/null
+++ b/testmaps/q1_detail_touching_water.map
@@ -0,0 +1,168 @@
+// Game: Quake
+// Format: Valve
+// entity 0
+{
+"mapversion" "220"
+"classname" "worldspawn"
+"wad" "deprecated/free_wad.wad;deprecated/fence.wad;deprecated/origin.wad;deprecated/hintskip.wad"
+"_wateralpha" "0.5"
+"_tb_def" "builtin:Quake.fgd"
+// brush 0
+{
+( -144 -192 48 ) ( -144 32 48 ) ( -144 -192 208 ) orangestuff8 [ 0 1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+( -144 -640 208 ) ( -128 -640 208 ) ( -144 -640 48 ) orangestuff8 [ -1 0 0 -16 ] [ 0 0 -1 48 ] 180 1 1
+( -144 -192 48 ) ( -128 -192 48 ) ( -144 32 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( -144 32 336 ) ( -128 32 336 ) ( -144 -192 336 ) orangestuff8 [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 180 1 1
+( -144 32 48 ) ( -128 32 48 ) ( -144 32 208 ) orangestuff8 [ 1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( -128 -192 48 ) ( -128 -192 208 ) ( -128 32 48 ) orangestuff8 [ 0 1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 1
+{
+( -128 32 208 ) ( -128 16 208 ) ( -128 32 48 ) orangestuff8 [ 0 1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+( 96 16 208 ) ( 96 16 48 ) ( -128 16 208 ) orangestuff8 [ 1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( -128 32 48 ) ( -128 16 48 ) ( 96 32 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 96 32 336 ) ( 96 16 336 ) ( -128 32 336 ) orangestuff8 [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 180 1 1
+( 96 32 208 ) ( -128 32 208 ) ( 96 32 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( 464 32 48 ) ( 464 16 48 ) ( 464 32 208 ) orangestuff8 [ 0 -1 0 -16 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 2
+{
+( -128 -656 48 ) ( -128 -640 48 ) ( -128 -656 208 ) orangestuff8 [ 0 1 0 -32 ] [ 0 0 -1 48 ] 0 1 1
+( 464 -656 48 ) ( 240 -656 48 ) ( 464 -656 208 ) orangestuff8 [ -1 0 0 32 ] [ 0 0 -1 48 ] 180 1 1
+( 464 -656 48 ) ( 464 -640 48 ) ( 240 -656 48 ) orangestuff8 [ 1 0 0 -32 ] [ 0 -1 0 32 ] 180 1 1
+( 240 -656 336 ) ( 240 -640 336 ) ( 464 -656 336 ) orangestuff8 [ -1 0 0 32 ] [ 0 -1 0 32 ] 180 1 1
+( 240 -640 48 ) ( 464 -640 48 ) ( 240 -640 208 ) orangestuff8 [ -1 0 0 32 ] [ 0 0 -1 48 ] 180 1 1
+( 464 -656 208 ) ( 464 -640 208 ) ( 464 -656 48 ) orangestuff8 [ 0 -1 0 32 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 3
+{
+( -128 -176 352 ) ( -128 -176 336 ) ( -128 16 352 ) sky3 [ 0 1 0 16 ] [ 0 0 -1 64 ] 0 1 1
+( 96 -640 352 ) ( 96 -640 336 ) ( -128 -640 352 ) sky3 [ -1 0 0 -16 ] [ 0 0 -1 64 ] 180 1 1
+( 96 16 336 ) ( -128 16 336 ) ( 96 -176 336 ) sky3 [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 180 1 1
+( 96 16 352 ) ( 96 -176 352 ) ( -128 16 352 ) sky3 [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 180 1 1
+( -128 16 352 ) ( -128 16 336 ) ( 96 16 352 ) sky3 [ 1 0 0 16 ] [ 0 0 -1 64 ] 180 1 1
+( 464 16 352 ) ( 464 16 336 ) ( 464 -176 352 ) sky3 [ 0 -1 0 -16 ] [ 0 0 -1 64 ] 0 1 1
+}
+// brush 4
+{
+( 464 -432 208 ) ( 464 -656 208 ) ( 464 -432 48 ) orangestuff8 [ 0 -1 0 32 ] [ 0 0 -1 48 ] 0 1 1
+( 480 -656 48 ) ( 464 -656 48 ) ( 480 -656 208 ) orangestuff8 [ -1 0 0 32 ] [ 0 0 -1 48 ] 180 1 1
+( 480 -432 48 ) ( 464 -432 48 ) ( 480 -656 48 ) orangestuff8 [ 1 0 0 -32 ] [ 0 -1 0 32 ] 180 1 1
+( 480 -656 336 ) ( 464 -656 336 ) ( 480 -432 336 ) orangestuff8 [ -1 0 0 32 ] [ 0 -1 0 32 ] 180 1 1
+( 480 16 208 ) ( 464 16 208 ) ( 480 16 48 ) orangestuff8 [ 1 0 0 -32 ] [ 0 0 -1 48 ] 180 1 1
+( 480 -656 208 ) ( 480 -432 208 ) ( 480 -656 48 ) orangestuff8 [ 0 -1 0 32 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 5
+{
+( 304 -304 64 ) ( 304 -288 64 ) ( 304 -288 192 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+( 176 -320 64 ) ( 256 -320 192 ) ( 256 -320 64 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 48 ] 180 1 1
+( -128 16 48 ) ( -128 -176 48 ) ( 96 16 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( -128 -176 64 ) ( -128 16 64 ) ( 96 -176 64 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 128 -192 64 ) ( 224 -192 64 ) ( 224 -192 192 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( 464 -176 48 ) ( 464 -176 64 ) ( 464 16 48 ) orangestuff8 [ 0 -1 0 -16 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 6
+{
+( 160 -288 -32 ) ( 160 -240 -32 ) ( 160 -240 96 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+( 176 -320 -32 ) ( 256 -320 96 ) ( 256 -320 -32 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 -48 ] 180 1 1
+( -128 16 -48 ) ( -128 -176 -48 ) ( 96 16 -48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( -128 -176 -32 ) ( -128 16 -32 ) ( 96 -176 -32 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 128 -192 -32 ) ( 224 -192 -32 ) ( 224 -192 96 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 -48 ] 180 1 1
+( 304 -304 -32 ) ( 304 -288 96 ) ( 304 -288 -32 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 -48 ] 0 1 1
+}
+// brush 7
+{
+( -128 16 48 ) ( -128 16 64 ) ( -128 -176 48 ) orangestuff8 [ 0 1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+( 176 -320 64 ) ( 256 -320 192 ) ( 256 -320 64 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 48 ] 180 1 1
+( -128 16 48 ) ( -128 -176 48 ) ( 96 16 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( -128 -176 64 ) ( -128 16 64 ) ( 96 -176 64 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 128 -192 64 ) ( 224 -192 64 ) ( 224 -192 192 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( 160 -288 64 ) ( 160 -240 192 ) ( 160 -240 64 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 8
+{
+( 304 -288 -32 ) ( 304 -240 -32 ) ( 304 -240 96 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+( 192 -320 -32 ) ( 272 -320 96 ) ( 272 -320 -32 ) orangestuff8 [ 1 0 0 -32 ] [ 0 0 -1 -48 ] 180 1 1
+( -112 16 -48 ) ( -112 -176 -48 ) ( 112 16 -48 ) orangestuff8 [ 1 0 0 0 ] [ 0 -1 0 -16 ] 180 1 1
+( -112 -176 48 ) ( -112 16 48 ) ( 112 -176 48 ) orangestuff8 [ 1 0 0 0 ] [ 0 -1 0 -16 ] 180 1 1
+( 144 -192 -32 ) ( 240 -192 -32 ) ( 240 -192 96 ) orangestuff8 [ -1 0 0 32 ] [ 0 0 -1 -48 ] 180 1 1
+( 320 -304 -32 ) ( 320 -288 96 ) ( 320 -288 -32 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 -48 ] 0 1 1
+}
+// brush 9
+{
+( 144 -288 -32 ) ( 144 -240 -32 ) ( 144 -240 96 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+( 32 -320 -32 ) ( 112 -320 96 ) ( 112 -320 -32 ) orangestuff8 [ 1 0 0 0 ] [ 0 0 -1 -48 ] 180 1 1
+( -272 16 -48 ) ( -272 -176 -48 ) ( -48 16 -48 ) orangestuff8 [ 1 0 0 32 ] [ 0 -1 0 -16 ] 180 1 1
+( -272 -176 48 ) ( -272 16 48 ) ( -48 -176 48 ) orangestuff8 [ 1 0 0 32 ] [ 0 -1 0 -16 ] 180 1 1
+( -16 -192 -32 ) ( 80 -192 -32 ) ( 80 -192 96 ) orangestuff8 [ -1 0 0 0 ] [ 0 0 -1 -48 ] 180 1 1
+( 160 -304 -32 ) ( 160 -288 96 ) ( 160 -288 -32 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 -48 ] 0 1 1
+}
+// brush 10
+{
+( 160 -192 -48 ) ( 160 -191 -48 ) ( 160 -192 -47 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+( 160 -192 -48 ) ( 160 -192 -47 ) ( 161 -192 -48 ) orangestuff8 [ -1.0000000000000002 0 0 0 ] [ 0 0 -1.0000000000000002 -48 ] 0 1 1
+( 160 -192 -48 ) ( 161 -192 -48 ) ( 160 -191 -48 ) orangestuff8 [ 0 -1.0000000000000002 0 16 ] [ -1.0000000000000002 0 0 48 ] 0 1 1
+( 304 -176 48 ) ( 304 -175 48 ) ( 305 -176 48 ) orangestuff8 [ 0 -1.0000000000000002 0 16 ] [ 1.0000000000000002 0 0 -16 ] 0 1 1
+( 304 -176 -32 ) ( 305 -176 -32 ) ( 304 -176 -31 ) orangestuff8 [ 1.0000000000000002 0 0 -48 ] [ 0 0 -1.0000000000000002 -48 ] 0 1 1
+( 304 -176 -32 ) ( 304 -176 -31 ) ( 304 -175 -32 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+}
+// brush 11
+{
+( 160 -336 -48 ) ( 160 -335 -48 ) ( 160 -336 -47 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+( 160 -336 -48 ) ( 160 -336 -47 ) ( 161 -336 -48 ) orangestuff8 [ -1.0000000000000002 0 0 16 ] [ 0 0 -1.0000000000000002 -48 ] 0 1 1
+( 160 -336 -48 ) ( 161 -336 -48 ) ( 160 -335 -48 ) orangestuff8 [ 0 -1.0000000000000002 0 16 ] [ -1.0000000000000002 0 0 48 ] 0 1 1
+( 304 -320 48 ) ( 304 -319 48 ) ( 305 -320 48 ) orangestuff8 [ 0 -1.0000000000000002 0 16 ] [ 1.0000000000000002 0 0 -16 ] 0 1 1
+( 304 -320 -32 ) ( 305 -320 -32 ) ( 304 -320 -31 ) orangestuff8 [ 1.0000000000000002 0 0 32 ] [ 0 0 -1.0000000000000002 -48 ] 0 1 1
+( 304 -320 -32 ) ( 304 -320 -31 ) ( 304 -319 -32 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 -48 ] 0 1 1
+}
+// brush 12
+{
+( -128 -192 64 ) ( -128 16 48 ) ( -128 16 64 ) orangestuff8 [ 0 1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+( 464 -192 64 ) ( -128 -192 48 ) ( -128 -192 64 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 48 ] 180 1 1
+( 464 16 48 ) ( -128 -192 48 ) ( 464 -192 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 464 16 64 ) ( -128 -192 64 ) ( -128 16 64 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 464 16 64 ) ( -128 16 48 ) ( 464 16 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( 464 16 64 ) ( 464 -192 48 ) ( 464 -192 64 ) orangestuff8 [ 0 -1 0 -16 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 13
+{
+( -128 -640 64 ) ( -128 -320 48 ) ( -128 -320 64 ) orangestuff8 [ 0 1 0 16 ] [ 0 0 -1 48 ] 0 1 1
+( 464 -640 64 ) ( -128 -640 48 ) ( -128 -640 64 ) orangestuff8 [ -1 0 0 -16 ] [ 0 0 -1 48 ] 180 1 1
+( 464 -320 48 ) ( -128 -640 48 ) ( 464 -640 48 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 464 -320 64 ) ( -128 -640 64 ) ( -128 -320 64 ) orangestuff8 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 180 1 1
+( 464 -320 64 ) ( -128 -320 48 ) ( 464 -320 48 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 48 ] 180 1 1
+( 464 -320 64 ) ( 464 -640 48 ) ( 464 -640 64 ) orangestuff8 [ 0 -1 0 -16 ] [ 0 0 -1 48 ] 0 1 1
+}
+// brush 14
+{
+( 160 -320 32 ) ( 160 -319 32 ) ( 160 -320 33 ) *swater5 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( 240 -320 64 ) ( 160 -240 64 ) ( 160 -240 192 ) *swater5 [ 0.7071067811865476 -0.7071067811865476 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( 256 -320 32 ) ( 256 -320 33 ) ( 257 -320 32 ) *swater5 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( 256 -320 -32 ) ( 257 -320 -32 ) ( 256 -319 -32 ) *swater5 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( 304 -240 64 ) ( 304 -239 64 ) ( 305 -240 64 ) *swater5 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( 304 -192 48 ) ( 305 -192 48 ) ( 304 -192 49 ) *swater5 [ -1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( 304 -240 48 ) ( 304 -240 49 ) ( 304 -239 48 ) *swater5 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+}
+}
+// entity 1
+{
+"classname" "info_player_start"
+"origin" "-56 -96 120"
+}
+// entity 2
+{
+"classname" "ambient_drip"
+"origin" "168 -296 200"
+}
+// entity 3
+{
+"classname" "func_detail"
+// brush 0
+{
+( 160 -320 32 ) ( 160 -319 32 ) ( 160 -320 33 ) archeo3 [ 0 -1 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( 256 -320 32 ) ( 256 -320 33 ) ( 257 -320 32 ) archeo3 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1
+( 256 -320 -32 ) ( 257 -320 -32 ) ( 256 -319 -32 ) archeo3 [ -1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( 304 -240 64 ) ( 304 -239 64 ) ( 305 -240 64 ) archeo3 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1
+( 240 -320 64 ) ( 160 -240 192 ) ( 160 -240 64 ) archeo3 [ 0.7071067811865476 -0.7071067811865476 0 0 ] [ 0 0 -1 0 ] 0 1 1
+}
+}
diff --git a/tests/test_common.cc b/tests/test_common.cc
index de5c8311..f5c8ab09 100644
--- a/tests/test_common.cc
+++ b/tests/test_common.cc
@@ -102,6 +102,9 @@ TEST_SUITE("common")
                 CHECK(solid_empty_cluster.is_empty(game));
                 // this is a bit weird...
                 CHECK(solid_empty_cluster.is_any_detail(game));
+
+                // check portal_can_see_through
+                CHECK(!game->portal_can_see_through(empty, solid_detail, true, true));
             }
         }
     }
diff --git a/tests/test_qbsp.cc b/tests/test_qbsp.cc
index a88cd0df..a208ccdb 100644
--- a/tests/test_qbsp.cc
+++ b/tests/test_qbsp.cc
@@ -868,6 +868,13 @@ TEST_CASE("q1_sealing_contents" * doctest::test_suite("testmaps_q1"))
     CHECK(prt.has_value());
 }
 
+TEST_CASE("q1_detail_touching_water" * doctest::test_suite("testmaps_q1"))
+{
+    const auto [bsp, bspx, prt] = LoadTestmapQ1("q1_detail_touching_water.map");
+
+    CHECK(prt.has_value());
+}
+
 TEST_CASE("detail_doesnt_remove_world_nodes" * doctest::test_suite("testmaps_q1"))
 {
     const auto [bsp, bspx, prt] = LoadTestmapQ1("qbsp_detail_doesnt_remove_world_nodes.map");