diff --git a/common/include/editor/editor.h b/common/include/editor/editor.h
index 01935c450..ea0fc5162 100644
--- a/common/include/editor/editor.h
+++ b/common/include/editor/editor.h
@@ -193,7 +193,7 @@ extern int is_free_vertex(int vi);
 //	Set existing vertex vnum to value *vp.
 int med_set_vertex(int vnum,const vertex &vp);
 
-extern void med_combine_duplicate_vertices(sbyte *vlp);
+void med_combine_duplicate_vertices(array<uint8_t, MAX_VERTICES> &);
 
 // Attach side newside of newseg to side destside of destseg.
 // Copies *newseg into global array Segments, increments Num_segments.
diff --git a/common/include/editor/esegment.h b/common/include/editor/esegment.h
index 6205caa0c..c612055e0 100644
--- a/common/include/editor/esegment.h
+++ b/common/include/editor/esegment.h
@@ -19,7 +19,7 @@ extern	int		AttachSide;				//	Side on segment to attach
 extern	int		Draw_all_segments;	// Set to 1 means draw_world draws all segments in Segments, else draw only connected segments
 extern	segment	*Markedsegp;			// Marked segment, used in conjunction with *Cursegp to form joints.
 extern	int		Markedside;				// Marked side on Markedsegp.
-extern  sbyte   Vertex_active[MAX_VERTICES]; // !0 means vertex is in use, 0 means not in use.
+extern array<uint8_t, MAX_VERTICES> Vertex_active; // !0 means vertex is in use, 0 means not in use.
 
 // The extra group in the following arrays is used for group rotation.
 extern 	group		GroupList[MAX_GROUPS+1];
diff --git a/similar/editor/eglobal.cpp b/similar/editor/eglobal.cpp
index bd2e89fad..555f424f6 100644
--- a/similar/editor/eglobal.cpp
+++ b/similar/editor/eglobal.cpp
@@ -42,7 +42,7 @@ int Markedside;          // Marked side on Markedsegp.
 
 int Draw_all_segments;   // Set to 1 means draw_world draws all segments in Segments, else draw only connected segments
 
-sbyte Vertex_active[MAX_VERTICES]; // !0 means vertex is in use, 0 means not in use.
+array<uint8_t, MAX_VERTICES> Vertex_active; // !0 means vertex is in use, 0 means not in use.
 
 selected_segment_array_t Selected_segs; // List of segment numbers currently selected
 
diff --git a/similar/editor/group.cpp b/similar/editor/group.cpp
index 158213323..64a8fe77b 100644
--- a/similar/editor/group.cpp
+++ b/similar/editor/group.cpp
@@ -433,7 +433,7 @@ static void create_group_list(const vsegptridx_t segp, group::segment_array_type
 #define MXV MAX_VERTICES
 
 // ------------------------------------------------------------------------------------------------
-static void duplicate_group(sbyte *vertex_ids, group::segment_array_type_t &segments)
+static void duplicate_group(array<uint8_t, MAX_VERTICES> &vertex_ids, group::segment_array_type_t &segments)
 {
 	int	v,new_vertex_id,sidenum;
 	group::segment_array_type_t new_segments;
@@ -529,7 +529,7 @@ static int med_copy_group(int delta_flag, const vsegptridx_t base_seg, int base_
 	int 			x;
 	int			new_current_group;
 	int 			c;
-	sbyte			in_vertex_list[MAX_VERTICES];
+	array<uint8_t, MAX_VERTICES> in_vertex_list;
 
 	if (IS_CHILD(base_seg->children[base_side])) {
 		editor_status("Error -- unable to copy group, base_seg:base_side must be free.");
@@ -659,7 +659,8 @@ static int med_copy_group(int delta_flag, const vsegptridx_t base_seg, int base_
 static int med_move_group(int delta_flag, const vsegptridx_t base_seg, int base_side, const vsegptridx_t group_seg, int group_side, const vms_matrix &orient_matrix, int orientation)
 {
 	int			v,vv,c,d;
-	sbyte			in_vertex_list[MAX_VERTICES], out_vertex_list[MAX_VERTICES];
+	array<uint8_t, MAX_VERTICES> in_vertex_list;
+	sbyte			out_vertex_list[MAX_VERTICES];
 	int			local_hvi;
 
 	if (IS_CHILD(base_seg->children[base_side]))
diff --git a/similar/editor/segment.cpp b/similar/editor/segment.cpp
index 68cea0ce7..2d27ce7a1 100644
--- a/similar/editor/segment.cpp
+++ b/similar/editor/segment.cpp
@@ -720,7 +720,7 @@ static void compress_segments(void)
 //	Combine duplicate vertices.
 //	If two vertices have the same coordinates, within some small tolerance, then assign
 //	the same vertex number to the two vertices, freeing up one of the vertices.
-void med_combine_duplicate_vertices(sbyte *vlp)
+void med_combine_duplicate_vertices(array<uint8_t, MAX_VERTICES> &vlp)
 {
 	int	v,w;