diff --git a/solidify/main.pov b/solidify/main.pov
index 487255c..bf107e2 100644
--- a/solidify/main.pov
+++ b/solidify/main.pov
@@ -14,7 +14,7 @@ light_source {
 }
 
 union {
-    Part
+    Part_batcvr
     pigment { rgb <0.9, 0.9, 0.9> }
     finish {
         brilliance 2
diff --git a/solidify/solid.c b/solidify/solid.c
index 0322fa7..90df6b5 100644
--- a/solidify/solid.c
+++ b/solidify/solid.c
@@ -47,25 +47,45 @@ static void height_field(const char *name, const struct face *f,
 }
 
 
-void povray(const struct solid *s)
+static void sanitize(const char *s, char *res)
+{
+	while (*s) {
+		if ((*s >= 'A' && *s <= 'Z') ||
+		    (*s >= 'a' && *s <= 'z') ||
+		    (*s >= '0' && *s <= '9') || *s == '_')
+			*res = *s;
+		else
+			*res = '_';
+		res++;
+		s++;
+	}
+	*res = 0;
+}
+
+
+void povray(const char *name, const struct solid *s)
 {
 	struct matrix m;
+	char tmp[1000]; /* @@@ enough */
 
 	m.a[0][0] = m.a[1][1] = 1;
 	m.a[0][1] = m.a[1][0] = 0;
 	m.b[0] = m.b[1] = 0;
 
-	height_field("top.pgm", s->a, &m);
-	height_field("bot.pgm", s->b, &m);
+	sprintf(tmp, "%s-top.pgm", name);
+	height_field(tmp, s->a, &m);
+	sprintf(tmp, "%s-bot.pgm", name);
+	height_field(tmp, s->b, &m);
 
 	/*
 	 * 1/65535 = 0.000015..., so we set the water level a bit lower, e.g.,
 	 * to 0.0001
 	 */
+	sanitize(name, tmp);
 	printf(
-"#declare Part =\n"
+"#declare Part_%s =\n"
 "    intersection {\n"
-"        height_field { pgm \"top.pgm\" water_level 0.00001 smooth }\n"
-"        height_field { pgm \"bot.pgm\" water_level 0.00001 smooth }\n"
-"    }\n");
+"        height_field { pgm \"%s-top.pgm\" water_level 0.00001 smooth }\n"
+"        height_field { pgm \"%s-bot.pgm\" water_level 0.00001 smooth }\n"
+"    }\n", tmp, name, name);
 }
diff --git a/solidify/solid.h b/solidify/solid.h
index 086d4cc..06a4ba8 100644
--- a/solidify/solid.h
+++ b/solidify/solid.h
@@ -19,6 +19,6 @@ struct solid {
 };
 
 
-void povray(const struct solid *s);
+void povray(const char *name, const struct solid *s);
 
 #endif /* !SOLID_H */
diff --git a/solidify/solidify.c b/solidify/solidify.c
index 413fe44..0fc41f7 100644
--- a/solidify/solidify.c
+++ b/solidify/solidify.c
@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <string.h>
 #include <locale.h>
 #include <gtk/gtk.h>
 
@@ -148,8 +149,15 @@ int main(int argc, char **argv)
 
 	save_project(prj);
 
-	if (!isatty(1))
-		povray(&prj->s);
+	if (!isatty(1)) {
+		const char *slash = strrchr(prj->name, '/');
+		char tmp[1000]; /* @@@ enough */
+
+		strcpy(tmp, slash ? slash+1 : prj->name);
+		if (strchr(tmp, '.'))
+			*strchr(tmp, '.') = 0;
+		povray(tmp, &prj->s);
+	}
 
 	return 0;
 }