Why are my Construct 3 tilemap collisions offset from the visible tiles?

The tilemap is on a layer with a parallax rate that is not 100x100. Parallax moves the visual position of the layer relative to the scroll, but collision shapes stay at the world position. A parallax of 50x50 means the tiles visually scroll at half speed while their collision stays at full speed, creating a growing offset.

Should my gameplay tilemap layer use parallax in Construct 3?

No. Gameplay layers (tilemaps the player collides with) should always have parallax set to 100x100, which means they scroll at the same rate as the camera. Parallax is for decorative background and foreground layers only.

How do I check the parallax rate on a Construct 3 layer?

Click on the layer in the Layers panel. The Properties panel shows Parallax X and Parallax Y. Both should be 100 for gameplay layers. Any other value means the visual position of objects on that layer will diverge from their collision position when the camera scrolls.

Fix: Construct 3 Tilemap Collision Offset After Scroll

Quick answer: Your tilemap is on a layer with parallax set to something other than 100×100. Parallax moves the visual position but collision shapes stay at the world position. Set gameplay layers to 100×100 parallax and reserve parallax for decorative layers only.

The player runs through your level and the first few screens feel fine. By the middle of the level, the character is falling through solid tiles, walking into invisible walls two tiles to the left, and getting stuck on empty air. The further the camera scrolls from the origin, the worse it gets. The bug is one property on one layer that should never have been changed.

What Parallax Does to Collisions

Parallax in Construct 3 is a rendering effect: it changes how fast a layer scrolls visually relative to the camera. A parallax of 50×50 means the layer scrolls at half the speed of the camera, creating a depth effect for backgrounds. A parallax of 100×100 means the layer scrolls at the same speed as the camera — no depth effect.

Crucially, parallax only affects the visual position of objects on the layer. The physics engine always uses the world position of collision shapes. When parallax moves the visual tiles but not their collision shapes, the two drift apart. At scroll position 0, they match. At scroll position 1000, a 50% parallax layer has a 500-pixel offset between visuals and collisions.

The Fix

Step 1: Set gameplay layers to 100×100.

Click the layer containing your tilemap in the Layers panel. In the Properties panel, set Parallax X to 100 and Parallax Y to 100. Save and preview. The collision shapes now scroll with the tiles.

Only decorative layers (far background, clouds, close foreground) should have parallax values other than 100. Any layer that contains objects the player collides with, including tilemaps, platforms, walls, and triggers, must be at 100×100.

Step 2: Check the tilemap origin.

Select the tilemap object in the layout. Its origin point should be at (0, 0) — the top-left corner. If the origin was accidentally moved (by editing the collision polygon in the Animations editor), every tile’s collision shape is shifted by that offset. Reset it to (0, 0).

Step 3: Check per-tile collision polygons.

Open the tilemap’s tile editor. Click on a tile and check its collision polygon. If the polygon is offset from the tile image (e.g. a few pixels to the right), every instance of that tile in the level will have an offset collision. Realign the polygon to match the tile’s visual bounds.

Debugging with Collision Overlay

In the preview, open the browser’s dev console and type:

// Show collision polygons (Construct 3 debug mode)
// Enable via Project Properties → Debug → Show collision polygons
// Or in event sheet:
Browser: Log "Debug: collision overlay enabled"

With the overlay active, scroll through the level. Collision polygons should exactly overlay their visual tiles at every scroll position. If they drift, parallax is the cause. If they are offset everywhere (not just after scrolling), the tilemap origin or per-tile polygon is the cause.

Multiple Tilemap Layers

Some projects use multiple tilemap layers: one for the ground, one for platforms, one for decorative foreground tiles. Only the gameplay tilemaps need 100×100 parallax. The decorative foreground can use 110×110 for a subtle depth effect without affecting collisions — as long as it has no collision polygons enabled.

Be especially careful with “near-foreground” layers at parallax 105×105. Developers sometimes put decorative tiles on these layers and forget that Construct still checks their collision shapes. Either disable collisions on the decorative tilemap or keep it at 100×100.

Verifying the Fix

Scroll the camera 2000 pixels to the right and check if collisions match tiles. If they do, the fix is working. Repeat vertically. The test must happen at a large scroll distance because small scroll distances produce small offsets that are hard to notice.

“Parallax is a visual effect. Physics does not know it exists. Any layer where the player touches things must have parallax at 100. This is the single most common Construct 3 tilemap bug.”

Related Issues

For broader tilemap collision problems, see Construct 3 tilemap collision not working. For collision detection between objects, see Construct 3 collision not detected between objects.

Before adding parallax to any layer, ask: does this layer have collision shapes? If yes, do not add parallax. Ever.