diff --git a/polymer/eduke32/build/include/baselayer.h b/polymer/eduke32/build/include/baselayer.h
index e73361960..488aaced0 100644
--- a/polymer/eduke32/build/include/baselayer.h
+++ b/polymer/eduke32/build/include/baselayer.h
@@ -104,7 +104,6 @@ int32_t handleevents(void);
 extern inline void idle(void);
 extern inline void idle_waitevent(void);
 extern inline void idle_waitevent_timeout(uint32_t timeout);
-extern void debug_sleep(int32_t ms);
 
 extern void (*keypresscallback)(int32_t,int32_t);
 extern void (*mousepresscallback)(int32_t,int32_t);
diff --git a/polymer/eduke32/build/src/build.c b/polymer/eduke32/build/src/build.c
index fdb4e73bd..daccb2354 100644
--- a/polymer/eduke32/build/src/build.c
+++ b/polymer/eduke32/build/src/build.c
@@ -444,11 +444,11 @@ int32_t app_main(int32_t argc, const char **argv)
         if (j > k) { k = j; whitecol = i; }
     }
 
-    k = clipmapinfo_load("_clipshape_.map");
+    k = clipmapinfo_load("_clipshape0.map");
     if (k==0)
-        initprintf("Loaded sprite clipping map from \"_clipshape_.map\"\n");
+        initprintf("Loaded sprite clipping map.\n");
     else if (k>0)
-        initprintf("There was an error loading the sprite clipping map from \"_clipshape_.map\" (status %d).\n", k);
+        initprintf("There was an error loading the sprite clipping map (status %d).\n", k);
 
     for (i=0; i<MAXSECTORS; i++) sector[i].extra = -1;
     for (i=0; i<MAXWALLS; i++) wall[i].extra = -1;
@@ -2433,7 +2433,10 @@ void overheadeditor(void)
                                 sprite[i].y >= highlighty1 && sprite[i].y <= highlighty2)
                             {
                                 if (!sub)
-                                    show2dsprite[i>>3] |= (1<<(i&7));
+                                {
+                                    if (sprite[i].sectnum >= 0)  // don't allow to select sprites in null space
+                                        show2dsprite[i>>3] |= (1<<(i&7));
+                                }
                                 else
                                     show2dsprite[i>>3] &= ~(1<<(i&7));
                             }
@@ -2545,9 +2548,12 @@ void overheadeditor(void)
 
                         setsprite(j,(vec3_t *)&sprite[j]);
 
-                        tempint = ((tilesizy[sprite[j].picnum]*sprite[j].yrepeat)<<2);
-                        sprite[j].z = max(sprite[j].z,getceilzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y)+tempint);
-                        sprite[j].z = min(sprite[j].z,getflorzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y));
+                        tempint = (tilesizy[sprite[j].picnum]*sprite[j].yrepeat)<<2;
+                        if (sprite[j].sectnum>=0)
+                        {
+                            sprite[j].z = max(sprite[j].z, getceilzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y)+tempint);
+                            sprite[j].z = min(sprite[j].z, getflorzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y));
+                        }
                     }
                 }
             }
@@ -2559,8 +2565,11 @@ void overheadeditor(void)
 
                 tempint = ((tilesizy[sprite[j].picnum]*sprite[j].yrepeat)<<2);
 
-                sprite[j].z = max(sprite[j].z, getceilzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y)+tempint);
-                sprite[j].z = min(sprite[j].z, getflorzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y));
+                if (sprite[j].sectnum>=0)
+                {
+                    sprite[j].z = max(sprite[j].z, getceilzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y)+tempint);
+                    sprite[j].z = min(sprite[j].z, getflorzofslope(sprite[j].sectnum,sprite[j].x,sprite[j].y));
+                }
             }
 
             if ((pointhighlight&0xc000) == 0)
@@ -2631,7 +2640,7 @@ SKIP:
 //                    updatesector(mousxplc,mousyplc,&cursectorhighlight);
                     cursectorhighlight = -1;
                     for (i=0; i<highlightsectorcnt; i++)
-                        if (inside(mousxplc, mousyplc, highlightsector[i]))
+                        if (inside(mousxplc, mousyplc, highlightsector[i])==1)
                         {
                             cursectorhighlight = highlightsector[i];
                             break;
@@ -2744,15 +2753,15 @@ SKIP:
                             dragpoint(pointhighlight,dax,day);
                         else if ((pointhighlight&0xc000) == 16384)
                         {
-                            int32_t daspr = pointhighlight&16383;
+                            int32_t daspr=pointhighlight&16383, osec=sprite[daspr].sectnum;
                             vec3_t vec, ovec;
 
                             Bmemcpy(&ovec, (vec3_t *)&sprite[daspr], sizeof(vec3_t));
                             vec.x = dax;
                             vec.y = day;
                             vec.z = sprite[daspr].z;
-                            if (setsprite(daspr, &vec) == -1)
-                                Bmemcpy(&sprite[daspr], &ovec, sizeof(vec3_t));                            
+                            if (setsprite(daspr, &vec) == -1 && osec>=0)
+                                Bmemcpy(&sprite[daspr], &ovec, sizeof(vec3_t));
 /*
                             daz = ((tilesizy[sprite[daspr].picnum]*sprite[daspr].yrepeat)<<2);
 
diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index 74ed985d9..ab30c7d27 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -215,6 +215,10 @@ static int16_t *sectoidx, *sectq;  // [numsectors]
 static int16_t pictoidx[MAXTILES];  // maps tile num to clipinfo[] index
 static int16_t *tempictoidx;
 
+static sectortype *loadsector;
+static walltype *loadwall;
+static spritetype *loadsprite;
+
 // sectoidx bits
 #define CM_NONE (CM_MAX<<1)
 #define CM_SOME (CM_NONE-1)
@@ -243,10 +247,6 @@ static void clipmapinfo_init()
 {
     int32_t i;
 
-    if (clipmapinfo.sector) { Bfree(clipmapinfo.sector); clipmapinfo.sector=NULL; }
-    if (clipmapinfo.wall) { Bfree(clipmapinfo.wall); clipmapinfo.wall=NULL; }
-    clipmapinfo.numsectors = clipmapinfo.numwalls = 0;
-
     numclipmaps = 0;
     numclipsects = 0;
 
@@ -256,6 +256,14 @@ static void clipmapinfo_init()
 
     for (i=0; i<MAXTILES; i++)
         pictoidx[i]=-1;
+
+    if (loadsector) { Bfree(loadsector); loadsector=NULL; }
+    if (loadwall) { Bfree(loadwall); loadwall=NULL; }
+    if (loadsprite) { Bfree(loadsprite); loadsprite=NULL; }
+
+    clipmapinfo.numsectors = clipmapinfo.numwalls = 0;
+    clipmapinfo.sector=NULL;
+    clipmapinfo.wall=NULL;
 }
 
 int32_t clipmapinfo_load(char *filename)
@@ -263,16 +271,94 @@ int32_t clipmapinfo_load(char *filename)
     int32_t i,k,w, px,py,pz;
     int16_t ang,cs;
 
+    char fn[BMAX_PATH];
+    int32_t slen, fi, fisec[10], fispr[10];
+    int32_t ournumsectors=0, ournumwalls=0, ournumsprites=0, numsprites;
+
     clipmapinfo_init();
 
+    loadsector = Bmalloc(MAXSECTORS * sizeof(sectortype));
+    loadwall = Bmalloc(MAXWALLS * sizeof(walltype));
+    loadsprite = Bmalloc(MAXSPRITES * sizeof(spritetype));
+
+    if (!loadsector || !loadwall || !loadsprite)
+    {
+        clipmapinfo_init();
+        return 1;
+    }
+
+    Bmemset(fisec, 0, sizeof(fisec));
+    Bmemset(fispr, 0, sizeof(fispr));
+
+    Bstrcpy(fn, filename);
+    slen = Bstrlen(fn);
+
     quickloadboard = 1;
-    i = loadboard(filename, 0, &px,&py,&pz, &ang,&cs);
+    for (fi='0'; fi<='9'; fi++)
+    {
+        fisec[fi-'0'] = ournumsectors;
+        fispr[fi-'0'] = ournumsprites;
+
+        fn[slen-5] = fi;
+        i = loadboard(fn, 0, &px,&py,&pz, &ang,&cs);
+        if (i<0)
+            continue;
+
+        for (numsprites=0; numsprites<MAXSPRITES; numsprites++)
+            if (sprite[numsprites].statnum == MAXSTATUS)
+                break;
+
+        if (ournumsectors+numsectors>MAXSECTORS ||
+            ournumwalls+numwalls>MAXWALLS ||
+            ournumsprites+numsprites>MAXSPRITES)
+        {
+            initprintf("clip map: warning: exceeded limits when loading %s, aborting.\n", fn);
+            break;
+        }
+
+        Bmemcpy(loadsector+ournumsectors, sector, numsectors*sizeof(sectortype));
+        Bmemcpy(loadwall+ournumwalls, wall, numwalls*sizeof(walltype));
+        Bmemcpy(loadsprite+ournumsprites, sprite, numsprites*sizeof(spritetype));
+        for (i=ournumsectors; i<ournumsectors+numsectors; i++)
+            loadsector[i].wallptr += ournumwalls;
+        for (i=ournumwalls; i<ournumwalls+numwalls; i++)
+        {
+            if (loadwall[i].point2>=0)
+                loadwall[i].point2 += ournumwalls;
+            if (loadwall[i].nextwall>=0)
+            {
+                loadwall[i].nextwall += ournumwalls;
+                loadwall[i].nextsector += ournumsectors;
+            }
+        }
+        for (i=ournumsprites; i<ournumsprites+numsprites; i++)
+            if (loadsprite[i].sectnum>=0)
+                loadsprite[i].sectnum += ournumsectors;
+        ournumsectors += numsectors;
+        ournumwalls += numwalls;
+        ournumsprites += numsprites;
+    }
     quickloadboard = 0;
-    if (i<0)
-        return i;
+
+    if (ournumsectors==0 || ournumwalls==0 || ournumsprites==0)  // nothing loaded
+    {
+        clipmapinfo_init();
+        return -1;
+    }
+
+    loadsector = Brealloc(loadsector, ournumsectors*sizeof(sectortype));
+    loadwall = Brealloc(loadwall, ournumwalls*sizeof(walltype));
+
+    Bmemcpy(sector, loadsector, ournumsectors*sizeof(sectortype));
+    Bmemcpy(wall, loadwall, ournumwalls*sizeof(walltype));
+    Bmemcpy(sprite, loadsprite, ournumsprites*sizeof(spritetype));
+    numsectors = ournumsectors;
+    numwalls = ournumwalls;
+
+    //  vvvv    don't use headsprite[sect,stat]!   vvvv
 
     sectoidx = Bmalloc(numsectors*sizeof(sectoidx[0]));
-    if (!sectoidx)
+    if (!sectoidx || !sector || !wall)
     {
         clipmapinfo_init();
         return 1;
@@ -333,8 +419,12 @@ int32_t clipmapinfo_load(char *filename)
             {
                 if (sectoidx[k]&CM_SOME)
                 {
-                    initprintf("clip map: error: tried to chain picnum %d (sprite %d) in sector %d which"
-                               " already belongs to picnum %d.\n", pn, i, k, clipinfo[sectoidx[k]].picnum);
+                    for (fi=0; fi<9; fi++)
+                        if (k>=fisec[fi])
+                            break;
+                    initprintf("clip map %d: error: tried to chain picnum %d (sprite %d) in sector %d which"
+                               " already belongs to picnum %d.\n", fi, pn, i-fispr[fi], k-fisec[fi],
+                               clipinfo[sectoidx[k]].picnum);
                     clipmapinfo_init();
                     return 2;
                 }
@@ -353,8 +443,11 @@ int32_t clipmapinfo_load(char *filename)
             {
                 if (sprite[i].ang!=1536 && sprite[i].ang!=512)
                 {
-                    initprintf("clip map: warning: sprite %d pointing neither northward nor southward. %s"
-                               " will be wrong.", i, (sprite[i].cstat&48)==32 ? "Scaling and flipping" : "X-flipping");
+                    for (fi=0; fi<9; fi++)
+                        if (i>=fispr[fi])
+                            break;
+                    initprintf("clip map %d: warning: sprite %d pointing neither northward nor southward. %s will be wrong.\n",
+                               fi, i-fispr[fi], (sprite[i].cstat&48)==32 ? "Scaling and flipping" : "X-flipping");
                 }
             }
 
@@ -387,8 +480,11 @@ int32_t clipmapinfo_load(char *filename)
                         {
                             if (outersect>=0 && ns!=outersect)
                             {
-                                initprintf("clip map: error: encountered more than one outer sector"
-                                           " (%d and %d) for sprite %d.\n", outersect, ns, i);
+                                for (fi=0; fi<9; fi++)
+                                    if (ns>=fisec[fi])
+                                        break;
+                                initprintf("clip map %d: error: encountered more than one outer sector (%d and %d)"
+                                           " for sprite %d.\n", fi, outersect-fisec[fi], ns-fisec[fi], i-fispr[fi]);
                                 clipmapinfo_init();
                                 return 3;
                             }
@@ -398,9 +494,12 @@ int32_t clipmapinfo_load(char *filename)
                         }
                         else if (sectoidx[ns]!=numclipmaps)
                         {
-                            initprintf("clip map: error: encountered sector %d belonging to index %d"
+                            for (fi=0; fi<9; fi++)
+                                if (ns>=fisec[fi])
+                                    break;
+                            initprintf("clip map %d: error: encountered sector %d belonging to index %d"
                                        " while collecting sectors for sprite %d (index %d).\n",
-                                       ns, sectoidx[ns], i, numclipmaps);
+                                       fi, ns-fisec[fi], sectoidx[ns], i-fispr[fi], numclipmaps);
                             clipmapinfo_init();
                             return 4;
                         }
@@ -408,6 +507,13 @@ int32_t clipmapinfo_load(char *filename)
                 }
             } while (++scnt < numclipsects);
 
+            if (outersect==-1)
+            {
+                initprintf("clip map: INTERNAL ERROR: outersect==-1!\n");
+                clipmapinfo_init();
+                return 5;
+            }
+
             sectq[numclipsects++] = outersect;  // last is outer
             clipinfo[numclipmaps].qend = numclipsects-1;
 
@@ -418,13 +524,13 @@ int32_t clipmapinfo_load(char *filename)
             {
                 k = sectq[scnt];
 
-                sector[k].floorz -= z;
-                sector[k].ceilingz -= z;
-
                 x = sprite[i].x;
                 y = sprite[i].y;
                 z = sprite[i].z;
 
+                sector[k].floorz -= z;
+                sector[k].ceilingz -= z;
+
                 if (scnt==clipinfo[numclipmaps].qbeg)
                 {
                     // backup sprite tags since we'll discard sprites later
@@ -497,12 +603,14 @@ int32_t clipmapinfo_load(char *filename)
         }
     }
 
+    // yes, too much copying, but better than ugly code
+    Bmemcpy(loadsector, sector, ournumsectors*sizeof(sectortype));
+    Bmemcpy(loadwall, wall, ournumwalls*sizeof(walltype));
+
     clipmapinfo.numsectors = numsectors;
-    clipmapinfo.sector = Bmalloc(numsectors * sizeof(sectortype));
-    Bmemcpy(clipmapinfo.sector, sector, numsectors*sizeof(sectortype));
+    clipmapinfo.sector = loadsector;
     clipmapinfo.numwalls = numwalls;
-    clipmapinfo.wall = Bmalloc(numwalls * sizeof(walltype));
-    Bmemcpy(clipmapinfo.wall, wall, numwalls*sizeof(walltype));
+    clipmapinfo.wall = loadwall;
 
     for (i=0; i<MAXTILES; i++)
     {
@@ -510,7 +618,8 @@ int32_t clipmapinfo_load(char *filename)
             pictoidx[i]=tempictoidx[i];
     }
 
-    Bfree(tempictoidx);
+    Bfree(loadsprite); loadsprite=NULL;
+    Bfree(tempictoidx); tempictoidx=NULL;
 
     return 0;
 }
@@ -9597,7 +9706,11 @@ int32_t clipmove(vec3_t *vect, int16_t *sectnum,
             mulxdir = clipsprite_initindex(curidx, curspr, &clipsectcnt, vect);
         }
 
+
         dasect = clipsectorlist[clipsectcnt++];
+//if (curspr)
+//    initprintf("sprite %d/%d: sect %d/%d (%d)\n", clipspritecnt,clipspritenum, clipsectcnt,clipsectnum,dasect);
+
         sec = &sector[dasect];
         startwall = sec->wallptr; endwall = startwall + sec->wallnum;
         for (j=startwall,wal=&wall[startwall]; j<endwall; j++,wal++)
@@ -9633,8 +9746,8 @@ int32_t clipmove(vec3_t *vect, int16_t *sectnum,
                     sec2 = &sector[wal->nextsector];
                     if ((sec2->floorstat&1) == 0)
 //                        if (dasect==sectq[clipinfo[curidx].qend] || daz2 < daz-(1<<8))
-                            if (vect->z <= basez+(flordist-1))
-                                if (vect->z >= daz2-(flordist-1)) clipyou = 1;
+                            if (daz2-(flordist-1) <= vect->z && vect->z <= basez+(flordist-1))
+                                clipyou = 1;
                     if (clipyou == 0)
                     {
                         daz = getceilzofslope((int16_t)dasect,dax,day);
@@ -9642,8 +9755,8 @@ int32_t clipmove(vec3_t *vect, int16_t *sectnum,
                         basez = getceilzofslope(sectq[clipinfo[curidx].qend],dax,day);
                         if ((sec2->ceilingstat&1) == 0)
 //                            if (dasect==sectq[clipinfo[curidx].qend] || daz2 > daz+(1<<8))
-                                if (vect->z >= basez-(ceildist-1))
-                                    if (vect->z <= daz2+(ceildist-1)) clipyou = 1;
+                            if (basez-(ceildist-1) <= vect->z && vect->z <= daz2+(ceildist-1))
+                                clipyou = 1;
                     }
                 }
             }
@@ -9699,7 +9812,7 @@ int32_t clipmove(vec3_t *vect, int16_t *sectnum,
                 day = walldist; if (dx < 0) day = -day;
                 addclipline(x1+dax,y1+day,x2+dax,y2+day,objtype);
             }
-            else
+            else if (wal->nextsector>=0)
             {
                 for (i=clipsectnum-1; i>=0; i--)
                     if (wal->nextsector == clipsectorlist[i]) break;
@@ -9836,8 +9949,6 @@ int32_t clipmove(vec3_t *vect, int16_t *sectnum,
                 break;
             }
         }
-//if (clipspritenum)
-//    initprintf("sect %d/%d  sprite %d/%d\n", clipsectcnt,clipsectnum, clipspritecnt,clipspritenum);
     }
     while (clipsectcnt < clipsectnum || clipspritecnt < clipspritenum);
 
@@ -11213,11 +11324,6 @@ int32_t sectorofwall(int16_t theline)
 //
 int32_t getceilzofslope(int16_t sectnum, int32_t dax, int32_t day)
 {
-#if defined _WIN32 && defined DEBUGGINGAIDS
-    if (sectnum<0 || sectnum>numsectors)
-        debug_sleep(15000);
-#endif
-
     if (!(sector[sectnum].ceilingstat&2)) return(sector[sectnum].ceilingz);
 
     {
@@ -11238,11 +11344,6 @@ int32_t getceilzofslope(int16_t sectnum, int32_t dax, int32_t day)
 //
 int32_t getflorzofslope(int16_t sectnum, int32_t dax, int32_t day)
 {
-#if defined _WIN32 && defined DEBUGGINGAIDS
-    if (sectnum<0 || sectnum>numsectors)
-        debug_sleep(15000);
-#endif
-
     if (!(sector[sectnum].floorstat&2)) return(sector[sectnum].floorz);
 
     {
@@ -11267,11 +11368,6 @@ void getzsofslope(int16_t sectnum, int32_t dax, int32_t day, int32_t *ceilz, int
     walltype *wal, *wal2;
     sectortype *sec;
 
-#if defined _WIN32 && defined DEBUGGINGAIDS
-    if (sectnum<0 || sectnum>numsectors)
-        debug_sleep(15000);
-#endif
-
     sec = &sector[sectnum];
     *ceilz = sec->ceilingz; *florz = sec->floorz;
     if ((sec->ceilingstat|sec->floorstat)&2)
@@ -12067,19 +12163,27 @@ void draw2dscreen(int32_t posxe, int32_t posye, int16_t ange, int32_t zoome, int
     faketimerhandler();
 
     if ((zoome >= 256) || (editstatus == 0))
-        for (i=0; i<numsectors; i++)
-            for (j=headspritesect[i]; j>=0; j=nextspritesect[j])
+        for (j=0; j<MAXSPRITES; j++)
+            if (sprite[j].statnum<MAXSTATUS)
+//        for (i=0; i<numsectors; i++)
+//            for (j=headspritesect[i]; j>=0; j=nextspritesect[j])
                 if ((editstatus == 1) || (show2dsprite[j>>3]&pow2char[j&7]))
                 {
-                    col = 3;
-                    if (spritecol2d[sprite[j].picnum][0])
-                        col = spritecol2d[sprite[j].picnum][0];
-                    if ((sprite[j].cstat&1) > 0)
+                    if (sprite[j].sectnum<0)
+                        col = 4;  // red
+                    else
                     {
-                        col = 5;
-                        if (spritecol2d[sprite[j].picnum][1])
-                            col = spritecol2d[sprite[j].picnum][1];
+                        col = 3;
+                        if (spritecol2d[sprite[j].picnum][0])
+                            col = spritecol2d[sprite[j].picnum][0];
+                        else if ((sprite[j].cstat&1) > 0)
+                        {
+                            col = 5;
+                            if (spritecol2d[sprite[j].picnum][1])
+                                col = spritecol2d[sprite[j].picnum][1];
+                        }
                     }
+
                     if (editstatus == 1)
                     {
                         if ((pointhighlight-16384) >= 0 && (j+16384 == pointhighlight || ((sprite[j].x == sprite[pointhighlight-16384].x) && (sprite[j].y == sprite[pointhighlight-16384].y))))
diff --git a/polymer/eduke32/build/src/winlayer.c b/polymer/eduke32/build/src/winlayer.c
index 894e81417..08f534736 100644
--- a/polymer/eduke32/build/src/winlayer.c
+++ b/polymer/eduke32/build/src/winlayer.c
@@ -847,11 +847,6 @@ inline void idle(void)
     idle_waitevent();
 }
 
-void debug_sleep(int32_t ms)
-{
-    Sleep(ms);
-}
-
 //
 // setjoydeadzone() -- sets the dead and saturation zones for the joystick
 //
diff --git a/polymer/eduke32/samples/_clipshape0.map b/polymer/eduke32/samples/_clipshape0.map
new file mode 100644
index 000000000..c1a3b7afb
Binary files /dev/null and b/polymer/eduke32/samples/_clipshape0.map differ
diff --git a/polymer/eduke32/samples/a.m32 b/polymer/eduke32/samples/a.m32
index 6f9cdc272..6a0cded5c 100644
--- a/polymer/eduke32/samples/a.m32
+++ b/polymer/eduke32/samples/a.m32
@@ -23,6 +23,9 @@ define SFACTORSTEPS 100
 // color of various drawing enhancements
 define PREVIEW_DRAW_COLOR 11
 
+// 2d mode corruption checker interval, 120 = 1 second
+gamevar checkinterval 600 0
+
 // whether to use overridden aspect/range values when entering 3d mode (software/Polymost).
 // tweak with keys 7,8,9,0 on the top row
 gamevar use_custom_aspect 0 0  // this is now the same as r_usenewaspect
@@ -75,6 +78,7 @@ definequote 22 SECTOR[%d]: wallptr+wallnum=%d out of range: numwalls=%d!!!
 definequote 23 WALL[%d].POINT2=%d out of range: sector[%d].wallptr=%d, endwall=%d!!!
 definequote 24 WALL[%d].NEXTWALL=%d out of range: numwalls=%d!!!
 definequote 25 WALL[%d].NEXTSECTOR=%d out of range: numsectors=%d!!!
+definequote 26 SPRITE[%d].SECTNUM=%d. Expect problems!
 
 define PRSCALE 1000
 define MAXSPECULAR 100000
@@ -631,16 +635,6 @@ defstate previewdoors2d
     }
 ends
 
-onevent EVENT_DRAW2DSCREEN
-    ifge cursectnum 0
-    {
-        state connectlocators
-        state draw_prlightprojections
-    }
-
-    state previewdoors2d
-endevent
-
 
 // LOCATORS auto-incrementer
 onevent EVENT_INSERTSPRITE2D
@@ -1073,8 +1067,40 @@ defstate corruptchk
 			}
         }
     }
+
+    for i allsprites
+    {
+        ifl .sectnum 0
+        {
+            qsprintf TQUOTE 26 i .sectnum
+            quote TQUOTE printmessage16 TQUOTE
+        }
+    }
 ends
 
+
+gamevar d2d_lastcheck 0 0
+onevent EVENT_DRAW2DSCREEN
+    var tmp
+
+    ifge cursectnum 0
+    {
+        state connectlocators
+        state draw_prlightprojections
+    }
+
+    state previewdoors2d
+
+    ifl checkinterval 120, set checkinterval 120
+    set tmp totalclock, sub tmp checkinterval
+    ifl d2d_lastcheck tmp
+    {
+        set d2d_lastcheck totalclock
+        state corruptchk
+    }
+endevent
+
+
 defstate mkterrain
     var w2 w3 idx bit tmp sec
     var warned
diff --git a/polymer/eduke32/samples/spriteclip.txt b/polymer/eduke32/samples/spriteclip.txt
index c279c2bd9..cf8663722 100644
--- a/polymer/eduke32/samples/spriteclip.txt
+++ b/polymer/eduke32/samples/spriteclip.txt
@@ -4,8 +4,10 @@
 
 Sprite picnums can be assigned to a bunch of connected sectors so that
 clipping against these sprites will work as if it is carried out on the
-associated sectors. For this, a file named _clipshape_.map must be present
-at program start time that must be built to certain rules:
+associated sectors. For this, files named _clipshapeX.map (where X is
+in 0..9) should be present at program start time. Every such map must be
+built to certain rules, and loading many of them has the same effect as
+loading a single map with all sectors/walls/sprites thrown together.
 
 * Every sector that contains at least one white wall is considered an "outer" sector.
   Conversely, sectors with only red walls are "inner" (clipping) sectors.
@@ -25,21 +27,25 @@ at program start time that must be built to certain rules:
   orientation).
 
 * The sprites in inner sectors should point northward and should not have any orientation-
-  changing bits like x-flip or y-flip set. Setting centering is permitted, though.
+  changing bits like x-flip or y-flip set. Setting centering and a custom size is permitted,
+  though.
 
 * A set of picnums can be aliased to a layer. This is useful if "secondary" picnums
   are going to be used as decoration, for example. For this, set lotags and/or hitags
-  of any wall of an inner sector to the picnums to be aliased to values greater than 0.
-  If only one of them is set, it is taken as one picnum, otherwise as a both-sided inclusive
+  of any wall of an inner sector to the picnums to be aliased to layer containing the wall.
+  If only one of them is set, it is taken as a picnum, otherwise as a both-sided inclusive
   range, the order doesn't matter. The pigcop tank is present as an example in
-  samples/_clipshape_.map.
+  samples/_clipshape_.map. If a picnum has multiple layers, it is advisable to set the same
+  lotags/hitags for each layer. Note that you do not need to set tags unless you intend to
+  have more than one picnum to share a clipping shape.
 
 * The inner sectors of a given layer must be all interconnected (not necessarily directly)
   and for a layer there must be a unique outer sector.
 
 * Making the floor or ceiling of a sector parallaxed will disable clipping on it in certain
-  ways. Normally, there are four horizontal clipping planes (see the round table for an
-  example). Making the ceiling parallaxed disables the upper two, and analogously for the floor.
+  ways. Normally, there are four horizontal clipping planes per inner sector (see the round
+  table for an example). Making the ceiling parallaxed disables the upper two, and analogously
+  for the floor.
 
 * Making a sprite transparent will disable rotation around its origin to match a given sprite's
   angle. Use it on models with rotational symmetry.
@@ -48,7 +54,6 @@ at program start time that must be built to certain rules:
 Notes:
 ------
 
-* Only clipmove and getzrange are changed, so that hitscan weapons will still behave the old way.
 * The clipping will not change with rendering modes or options.
 
 
@@ -56,8 +61,12 @@ Known bugs:
 -----------
 
 * Flipping doesn't work correctly
-* The behaviour in Mapster32 and EDuke32 differs slightly, see the
-  round table arrangement in the test area of _clipshape_.map
+
+
+Predicted bugs:
+---------------
+
+* Clipping may not work across playing map sector boundaries, especially with large sprites.
 
 
  --Helixhorned
diff --git a/polymer/eduke32/source/astub.c b/polymer/eduke32/source/astub.c
index ccca9916c..5bd98fbb0 100644
--- a/polymer/eduke32/source/astub.c
+++ b/polymer/eduke32/source/astub.c
@@ -2082,7 +2082,7 @@ static void M32_MoveFX(void)
                 S_StopEnvSound(s->lotag, i);
             }
         }
-        else
+        else if (s->sectnum>=0)
         {
             ht = s->hitag;
 
@@ -9152,6 +9152,9 @@ void ExtPreCheckKeys(void) // just before drawrooms
                     int32_t start_wall = sector[isec].wallptr;
                     int32_t end_wall = start_wall + sector[isec].wallnum;
 
+                    if (isec<0)
+                        continue;
+
                     for (w = start_wall; w < end_wall; w++)
                     {
                         if (!wallflag[w])
@@ -9517,6 +9520,9 @@ void ExtAnalyzeSprites(void)
 
         if (shadepreview && !(tspr->cstat & 16))
         {
+            if (tspr->sectnum<0)
+                continue;
+
             if (sector[tspr->sectnum].ceilingstat&1)
             {
                 l = sector[tspr->sectnum].ceilingshade;
@@ -9804,6 +9810,9 @@ void ExtCheckKeys(void)
                     int32_t start_wall = sector[isec].wallptr;
                     int32_t end_wall = start_wall + sector[isec].wallnum;
 
+                    if (isec<0)
+                        continue;
+
                     for (w = start_wall; w < end_wall; w++)
                     {
                         if (wallflag[w])
@@ -10448,7 +10457,7 @@ static void EditSpriteData(int16_t spritenum)
                 if (editval)
                 {
                     printmessage16(edittext);
-                    i = getnumber16(edittext,sprite[spritenum].sectnum,MAXSECTORS-1,0);
+                    i = getnumber16(edittext,sprite[spritenum].sectnum,numsectors-1,0);
                     if (i != sprite[spritenum].sectnum)
                         changespritesect(spritenum,i);
                 }
diff --git a/polymer/eduke32/source/game.c b/polymer/eduke32/source/game.c
index df04f8856..50dbec574 100644
--- a/polymer/eduke32/source/game.c
+++ b/polymer/eduke32/source/game.c
@@ -9859,11 +9859,11 @@ CLEAN_DIRECTORY:
         Bfree(ptr);
     }
 
-    i = clipmapinfo_load("_clipshape_.map");
+    i = clipmapinfo_load("_clipshape0.map");
     if (i==0)
-        initprintf("Loaded sprite clipping map from \"_clipshape_.map\"\n");
+        initprintf("Loaded sprite clipping map.\n");
     else if (i>0)
-        initprintf("There was an error loading the sprite clipping map from \"_clipshape_.map\" (status %d).\n", i);
+        initprintf("There was an error loading the sprite clipping map (status %d).\n", i);
 
     OSD_Exec("autoexec.cfg");
 
diff --git a/polymer/eduke32/source/m32def.c b/polymer/eduke32/source/m32def.c
index ae2f77a86..e89777c92 100644
--- a/polymer/eduke32/source/m32def.c
+++ b/polymer/eduke32/source/m32def.c
@@ -189,7 +189,7 @@ const char *keyw[] =
     "jump",
     "{",
     "}",
-
+#if 0
     "setsector",
     "getsector",
     "setwall",
@@ -198,7 +198,7 @@ const char *keyw[] =
     "getsprite",
     "gettspr",
     "settspr",
-
+#endif
     "gamearray",
     "setarray",
     "getarraysize",
@@ -2387,6 +2387,7 @@ repeatcase:
         return 1;
 
 // *** more basic commands
+#if 0
     case CON_SETSECTOR:
     case CON_GETSECTOR:
     case CON_SETWALL:
@@ -2463,6 +2464,7 @@ repeatcase:
             C_GetNextVar();
         break;
     }
+#endif
 
     case CON_GAMEVAR:
         // syntax: gamevar <var1> <initial value> <flags>
diff --git a/polymer/eduke32/source/m32def.h b/polymer/eduke32/source/m32def.h
index d73507c71..0a46d21d0 100644
--- a/polymer/eduke32/source/m32def.h
+++ b/polymer/eduke32/source/m32def.h
@@ -270,6 +270,7 @@ enum ScriptKeywords_t
     CON_LEFTBRACE,
     CON_RIGHTBRACE,
 
+#if 0
 // more basic commands
     CON_SETSECTOR,
     CON_GETSECTOR,
@@ -279,6 +280,7 @@ enum ScriptKeywords_t
     CON_GETSPRITE, //+
     CON_GETTSPR,
     CON_SETTSPR,
+#endif
 
 // arrays
     CON_GAMEARRAY,
diff --git a/polymer/eduke32/source/m32exec.c b/polymer/eduke32/source/m32exec.c
index 2f85a9611..f13dcb4dc 100644
--- a/polymer/eduke32/source/m32exec.c
+++ b/polymer/eduke32/source/m32exec.c
@@ -55,7 +55,7 @@ instype *insptr;
 int32_t VM_Execute(int32_t once);
 static instype *x_sortingstateptr;
 
-#include "m32structures.c"
+//#include "m32structures.c"
 
 extern void message(const char *fmt, ...);
 
@@ -492,6 +492,7 @@ skip_check:
             VM_Execute(0);
             continue;
 
+#if 0
 // *** more basic commands
         case CON_SETSECTOR:
         case CON_GETSECTOR:
@@ -535,7 +536,7 @@ skip_check:
                 VM_AccessTsprite((tw==CON_SETTSPR)|2|4, lVar1, lLabelID, lVar2);
                 continue;
             }
-#if 0
+
         case CON_SETSPRITE:
             insptr++;
             {