diff --git a/source/blood/src/tile.cpp b/source/blood/src/tile.cpp
index bb1f2c8085..3dfd6573e3 100644
--- a/source/blood/src/tile.cpp
+++ b/source/blood/src/tile.cpp
@@ -122,7 +122,7 @@ int tileInit(char a1, const char *a2)
     for (int i = 0; i < kMaxTiles; i++)
     {
         if (voxelIndex[i] >= 0 && voxelIndex[i] < kMaxVoxels)
-            SetBitString((char*)voxreserve, voxelIndex[i]);
+            bitmap_set(voxreserve, voxelIndex[i]);
     }
 
     artLoaded = 1;
diff --git a/source/blood/src/view.cpp b/source/blood/src/view.cpp
index 7dc9c1f107..cceec90ce6 100644
--- a/source/blood/src/view.cpp
+++ b/source/blood/src/view.cpp
@@ -2677,7 +2677,7 @@ void viewProcessSprites(int32_t cX, int32_t cY, int32_t cZ, int32_t cA, int32_t
 
             int const nVoxel = tiletovox[pTSprite->picnum];
 
-            if (nVoxel != -1 && ((voxrotate[nVoxel>>3]&pow2char[nVoxel&7]) != 0 || (picanm[nRootTile].extra&7) == 7))
+            if (nVoxel != -1 && (bitmap_test(voxrotate, nVoxel) || (picanm[nRootTile].extra&7) == 7))
                 pTSprite->ang = (pTSprite->ang+((int)totalclock<<3))&2047;
         }
 
diff --git a/source/build/include/build.h b/source/build/include/build.h
index 16919dbb10..f531748159 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -1628,8 +1628,8 @@ extern GrowArray<char *> g_clipMapFiles;
 
 EXTERN int32_t nextvoxid;
 EXTERN intptr_t voxoff[MAXVOXELS][MAXVOXMIPS]; // used in KenBuild
-EXTERN int8_t voxreserve[(MAXVOXELS+7)>>3];
-EXTERN int8_t voxrotate[(MAXVOXELS+7)>>3];
+EXTERN int8_t voxreserve[bitmap_size(MAXVOXELS)];
+EXTERN int8_t voxrotate[bitmap_size(MAXVOXELS)];
 
 #ifdef USE_OPENGL
 // TODO: dynamically allocate this
diff --git a/source/build/src/defs.cpp b/source/build/src/defs.cpp
index 08f543e469..80ecf7a47e 100644
--- a/source/build/src/defs.cpp
+++ b/source/build/src/defs.cpp
@@ -1417,7 +1417,7 @@ static int32_t defsparser(scriptfile *script)
                 break; //voxel filename
 
             // begin downstream
-            while (nextvoxid < MAXVOXELS && (voxreserve[nextvoxid>>3]&(1<<(nextvoxid&7))))
+            while (nextvoxid < MAXVOXELS && bitmap_test(voxreserve, nextvoxid))
                 nextvoxid++;
             // end downstream
 
@@ -1961,7 +1961,7 @@ static int32_t defsparser(scriptfile *script)
             if (scriptfile_getbraces(script,&voxelend)) break;
 
             // begin downstream
-            while (nextvoxid < MAXVOXELS && (voxreserve[nextvoxid>>3]&(1<<(nextvoxid&7))))
+            while (nextvoxid < MAXVOXELS && bitmap_test(voxreserve, nextvoxid))
                 nextvoxid++;
             // end downstream
 
diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index 8a5617539b..f58e8c08ad 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -12252,7 +12252,7 @@ void vox_undefine(int32_t const tile)
         voxlock[voxindex][j] = CACHE1D_FREE;
         voxoff[voxindex][j] = 0;
     }
-    voxrotate[voxindex>>3] &= ~pow2char[voxindex&7];
+    bitmap_clear(voxrotate, voxindex);
     voxscale[voxindex] = 65536;
     voxflags[voxindex] = 0;
     tiletovox[tile] = -1;
diff --git a/source/exhumed/src/view.cpp b/source/exhumed/src/view.cpp
index 2e2e4dbfb5..24fa384ecc 100644
--- a/source/exhumed/src/view.cpp
+++ b/source/exhumed/src/view.cpp
@@ -243,7 +243,7 @@ static void analyzesprites()
             int const nRootTile = pTSprite->picnum;
             int const nVoxel = tiletovox[pTSprite->picnum];
 
-            if (nVoxel != -1 && ((voxrotate[nVoxel >> 3] & pow2char[nVoxel & 7]) != 0 || (picanm[nRootTile].extra & 7) == 7))
+            if (nVoxel != -1 && (bitmap_test(voxrotate, nVoxel) || (picanm[nRootTile].extra & 7) == 7))
                 pTSprite->ang = (pTSprite->ang + ((int)totalclock << 3)) & kAngleMask;
 
             if (pTSprite->picnum == 736) // invincibility sprite needs to always face player