diff --git a/addons/trenches/functions/fnc_blockTrench_place.sqf b/addons/trenches/functions/fnc_blockTrench_place.sqf
index f2aa062fe8..f602a871e0 100644
--- a/addons/trenches/functions/fnc_blockTrench_place.sqf
+++ b/addons/trenches/functions/fnc_blockTrench_place.sqf
@@ -8,6 +8,7 @@
  * 1: Position <ARRAY>
  * 2: Force - ignoring saftey checks (optional: false) <BOOL>
  * 3: Cut Grass (optional: false) <BOOL>
+ * 4: Dry Run - Just test if possible (can run on clients) <BOOL>
  *
  * Return Value:
  * <ARRAY>
@@ -21,10 +22,10 @@
  * Public: No
  */
 
-if (!isServer) exitWith { ERROR("function must be called on server"); [false, "server-only"]; };
+params [["_start2d", [], [[]]], ["_end2d", [], [[]]], ["_force", false, [false]], ["_cutGrass", false, [false]], ["_dryRun", false, [false]]];
+TRACE_4("blockTrench_place",_start2d,_end2d,_force,_dryRun);
 
-params [["_start2d", [], [[]]], ["_end2d", [], [[]]], ["_force", false, [false]], ["_cutGrass", false, [false]]];
-TRACE_3("blockTrench_place",_start2d,_end2d,_force);
+if ((!isServer) && {!_dryRun}) exitWith { ERROR("function must be called on server"); [false, "server-only"]; };
 
 scopeName "main";
 
@@ -71,6 +72,14 @@ if (_east) then {
 TRACE_3("",_east,_origin2D,_length);
 if (_length < 2) exitWith { [false, "too short"] breakOut "main" };
 
+if (_dryRun) exitWith { // return an array of block positions
+    private _positions = [];
+    for "_i" from 0 to _length do { // intentionally inclusive
+        _positions pushBack (_origin2D vectorAdd (if (_east) then {[(_i + 0.5) * _cellsize, 0]} else {[0, (_i + 0.5) * _cellsize]}));
+    };
+    [true, "dry run", _positions]
+};
+
 
 // Test and get block data
 private _blockData = [];
diff --git a/addons/zeus/functions/fnc_getModuleDestination.sqf b/addons/zeus/functions/fnc_getModuleDestination.sqf
index bc939445dc..b328201d6c 100644
--- a/addons/zeus/functions/fnc_getModuleDestination.sqf
+++ b/addons/zeus/functions/fnc_getModuleDestination.sqf
@@ -8,7 +8,7 @@
  * 1: Code to run when position is ready (will be passed the following array) <CODE>
  * - 0: Successful <BOOL>
  * - 1: Object <OBJECT>
- * - 2: Position ASL <ARRAY>
+ * - 2: Mouse Pos ASL <ARRAY>
  * - 3: State of Shift <BOOL>
  * - 4: State of Ctrl <BOOL>
  * - 5: State of Alt <BOOL>
@@ -16,6 +16,9 @@
  * 3: Icon image file <STRING> (default: "\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa")
  * 4: Icon color <ARRAY> (default: [1,0,0,1])
  * 5: Icon Angle <NUMBER> (default: 0)
+ * 6: Draw Code <CODE> (default: {})
+ * - 0: Object <OBJECT>
+ * - 1: Mouse Pos ASL <ARRAY>
  *
  * Return Value:
  * None
@@ -26,7 +29,7 @@
  * Public: No
  */
 
-params ["_object", "_code", ["_text", ""], ["_icon", "\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa"], ["_color", [1,0,0,1]], ["_angle", 0]];
+params ["_object", "_code", ["_text", ""], ["_icon", "\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa"], ["_color", [1,0,0,1]], ["_angle", 0], ["_drawCode", {}]];
 
 if (missionNamespace getVariable [QGVAR(moduleDestination_running), false]) exitWith {
     [false, _object, [0,0,0], false, false, false] call _code;
@@ -95,7 +98,7 @@ GVAR(moduleDestination_mapDrawEH) = [((findDisplay 312) displayCtrl 50), "draw",
 
 // Add draw EH for 3D camera view - draws the 3D icon and line
 [{
-    (_this select 0) params ["_object", "_code", "_text", "_icon", "_color", "_angle"];
+    (_this select 0) params ["_object", "_code", "_text", "_icon", "_color", "_angle", "_drawCode"];
     if ((isNull _object) || {isNull findDisplay 312} || {!isNull findDisplay 49}) then {
         TRACE_3("null-exit",isNull _object,isNull findDisplay 312,isNull findDisplay 49);
         GVAR(moduleDestination_running) = false;
@@ -104,6 +107,7 @@ GVAR(moduleDestination_mapDrawEH) = [((findDisplay 312) displayCtrl 50), "draw",
     if (GVAR(moduleDestination_running)) then {
         // Draw the 3d icon and line
         private _mousePosAGL = screenToWorld getMousePosition;
+        [_object, AGLToASL _mousePosAGL] call _drawCode;
         drawIcon3D [_icon, _color, _mousePosAGL, 1.5, 1.5, _angle, _text];
         drawLine3D [_mousePosAGL, ASLtoAGL (getPosASL _object), _color];;
     } else {
@@ -116,4 +120,4 @@ GVAR(moduleDestination_mapDrawEH) = [((findDisplay 312) displayCtrl 50), "draw",
         GVAR(moduleDestination_displayEHKeyboard) = nil;
         GVAR(moduleDestination_mapDrawEH) = nil;
     };
-}, 0, [_object, _code, _text, _icon, _color, _angle]] call CBA_fnc_addPerFrameHandler;
+}, 0, [_object, _code, _text, _icon, _color, _angle, _drawCode]] call CBA_fnc_addPerFrameHandler;
diff --git a/addons/zeus/functions/fnc_moduleLayTrench.sqf b/addons/zeus/functions/fnc_moduleLayTrench.sqf
index ae9d60f2f2..e92725138f 100644
--- a/addons/zeus/functions/fnc_moduleLayTrench.sqf
+++ b/addons/zeus/functions/fnc_moduleLayTrench.sqf
@@ -27,24 +27,31 @@ if !(["ace_trenches"] call EFUNC(common,isModLoaded)) exitWith {
     [LSTRING(RequiresAddon)] call FUNC(showMessage);
 };
 
-private _startPos = getPosASL _logic; // change position of logic to be aligned with grid
-getTerrainInfo params ["", "", "_cellsize"];
-_startPos = (_startPos select [0,2]) apply {_cellsize * round (_x / _cellsize)};
-_logic setPos _startPos;
+private _drawCode = {
+    params ["_object", "_mousePos"];
+    private _startPos = getPos _object;
+    ([_startPos, _mousePos, false, false, true] call EFUNC(trenches,blockTrench_place)) params ["_valid", "_reason", "_extra"];
+    if (_valid) then {
+        {
+            drawIcon3D ["\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa", [0,0,1,1], (_x select [0,2]) + [0], 1.5, 1.5, 0, ""];
+        } forEach _extra;
+    } else {
+        drawIcon3D ["\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa", [1,0,1,1], (_startPos select [0,2]) + [0], 1.5, 1.5, 0, ""];
+        drawIcon3D ["\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa", [1,0,1,1], (_mousePos select [0,2]) + [0], 1.5, 1.5, 0, ""];
+    };
+};
 
-
-// todo: it would be nice to show visually that trenches can only be dug north/south or east/west
 private _text = format ["%1 %2", LELSTRING(trenches,ConfirmDig), LLSTRING(ModuleLayTrenchline_Tooltip)];
 [_logic, {
     params ["_successful", "_logic", "_mousePosASL", "_shift"];
     TRACE_4("getModuleDestination",_successful,_logic,_mousePosASL,_shift);
 
+    if (isNull _logic) exitWith { WARNING("logic missing"); };
     private _startPosASL = getPosASL _logic;
     deleteVehicle _logic;
-    if (isNull _logic) exitWith { TRACE_1("exit",isNull _logic); };
     if (!_successful) exitWith { TRACE_1("exit",_successful); };
 
     private _args = [_startPosASL, _mousePosASL, _shift];
     TRACE_1("sending event",_args);
     [QEGVAR(trenches,layTrenchline), [ace_player, _args]] call CBA_fnc_serverEvent;
-}, _text, "\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa", [0, 1, 0, 1], 45] call FUNC(getModuleDestination);
+}, _text, "\a3\ui_f\data\IGUI\Cfg\Cursors\select_target_ca.paa", [0, 1, 0, 1], 45, _drawCode] call FUNC(getModuleDestination);