diff --git a/src/viewport-three/viewport-transient-state.ts b/src/viewport-three/viewport-transient-state.ts
index 6f5cabde..5f89a76e 100644
--- a/src/viewport-three/viewport-transient-state.ts
+++ b/src/viewport-three/viewport-transient-state.ts
@@ -1,4 +1,6 @@
 import type { Vec3 } from "../core/vector";
+import type { ToolMode } from "../core/tool-mode";
+import type { EntityKind } from "../entities/entity-instances";
 import type { ViewportPanelId } from "./viewport-layout";
 
 export interface BoxCreateViewportToolPreview {
@@ -7,7 +9,25 @@ export interface BoxCreateViewportToolPreview {
   center: Vec3 | null;
 }
 
-export type ViewportToolPreview = BoxCreateViewportToolPreview | { kind: "none" };
+export type ViewportPlacementPreviewTarget =
+  | {
+      kind: "entity";
+      entityKind: EntityKind;
+      audioAssetId: string | null;
+    }
+  | {
+      kind: "model-instance";
+      assetId: string;
+    };
+
+export interface PlacementViewportToolPreview {
+  kind: "placement";
+  sourcePanelId: ViewportPanelId;
+  target: ViewportPlacementPreviewTarget;
+  center: Vec3 | null;
+}
+
+export type ViewportToolPreview = BoxCreateViewportToolPreview | PlacementViewportToolPreview | { kind: "none" };
 
 export interface ViewportTransientState {
   toolPreview: ViewportToolPreview;
@@ -26,6 +46,25 @@ export function cloneViewportToolPreview(toolPreview: ViewportToolPreview): View
     return toolPreview;
   }
 
+  if (toolPreview.kind === "placement") {
+    return {
+      kind: "placement",
+      sourcePanelId: toolPreview.sourcePanelId,
+      target:
+        toolPreview.target.kind === "entity"
+          ? {
+              kind: "entity",
+              entityKind: toolPreview.target.entityKind,
+              audioAssetId: toolPreview.target.audioAssetId
+            }
+          : {
+              kind: "model-instance",
+              assetId: toolPreview.target.assetId
+            },
+      center: toolPreview.center === null ? null : { ...toolPreview.center }
+    };
+  }
+
   return {
     kind: "box-create",
     sourcePanelId: toolPreview.sourcePanelId,
@@ -42,6 +81,32 @@ export function areViewportToolPreviewsEqual(left: ViewportToolPreview, right: V
     return true;
   }
 
+  if (left.kind === "placement" && right.kind === "placement") {
+    if (left.sourcePanelId !== right.sourcePanelId) {
+      return false;
+    }
+
+    if (left.target.kind !== right.target.kind) {
+      return false;
+    }
+
+    if (left.target.kind === "entity" && right.target.kind === "entity") {
+      if (left.target.entityKind !== right.target.entityKind || left.target.audioAssetId !== right.target.audioAssetId) {
+        return false;
+      }
+    }
+
+    if (left.target.kind === "model-instance" && right.target.kind === "model-instance" && left.target.assetId !== right.target.assetId) {
+      return false;
+    }
+
+    if (left.center === null || right.center === null) {
+      return left.center === right.center;
+    }
+
+    return left.center.x === right.center.x && left.center.y === right.center.y && left.center.z === right.center.z;
+  }
+
   if (left.sourcePanelId !== right.sourcePanelId) {
     return false;
   }
@@ -52,3 +117,19 @@ export function areViewportToolPreviewsEqual(left: ViewportToolPreview, right: V
 
   return left.center.x === right.center.x && left.center.y === right.center.y && left.center.z === right.center.z;
 }
+
+export function isViewportToolPreviewCompatible(toolMode: ToolMode, toolPreview: ViewportToolPreview): boolean {
+  if (toolPreview.kind === "none") {
+    return true;
+  }
+
+  if (toolMode === "box-create") {
+    return toolPreview.kind === "box-create";
+  }
+
+  if (toolMode === "place") {
+    return toolPreview.kind === "placement";
+  }
+
+  return false;
+}