# Projection Mapping & Warp/Blend

Exaplay 3 integrates with **VIOSO** for professional geometric warping and edge blending across multiple projectors.

![Projection mapping overview](/files/bVu2kHeOVVdItwZ3ld8M)

## What Is Warp/Blend?

When multiple projectors cover the same surface (a curved screen, a building facade, or a multi-projector flat screen), two corrections are needed:

* **Geometric warping** — corrects lens distortion and keystoning so the image aligns with the physical surface.
* **Edge blending** — fades the overlapping region between adjacent projectors so the join is invisible.

VIOSO handles both using a calibration file (`.vwf`) produced by its auto-calibration software.

## Loading a Calibration File

1. Open **Config → Outputs**.
2. Select the output you want to warp.
3. Click **Load Warp File** and choose the `.vwf` file produced by VIOSO Calibrator.
4. The warp is applied immediately; toggle it on/off with the **Warp Enable** switch.

## Manual Warp Editor

For simple single-projector corrections without VIOSO Calibrator, Exaplay 3 includes a built-in grid warp editor.

Open it from **Config → Outputs → Edit Warp**.

![Warp editor with control points](/files/cJpfHug2VWAKUzAZHfLw)

### Control Points

The editor shows a grid of control points overlaid on the output. Each point can be moved to correct the geometry at that location.

| Action                  | How                                 |
| ----------------------- | ----------------------------------- |
| **Select point**        | Click the point                     |
| **Move point (fine)**   | Arrow keys (0.01 unit steps)        |
| **Move point (coarse)** | Shift + Arrow keys (0.1 unit steps) |
| **Cycle points**        | Tab / Shift+Tab                     |
| **Deselect**            | Escape or Enter                     |
| **Reset all**           | Click the Reset button              |

### Interpolation Mode

Choose between **Linear** and **Bicubic** interpolation from the Interpolation drop-down. Bicubic produces smoother results but requires more GPU.

## Edge Blending

Edge blending parameters are loaded from the VIOSO `.vwf` file. If you need to manually adjust the blend curve:

1. Open **Config → Outputs → Edge Blend**.
2. Adjust the **Blend Width** slider for each overlapping edge (0–100 %).
3. Adjust the **Gamma Curve** to control the blend falloff shape.

## Auto-Calibration (VIOSO)

If VIOSO AutoAlign is installed and a calibration camera is connected:

1. Go to the **Auto Calibration** view (`/autocalibration`).
2. Follow the on-screen wizard.
3. The resulting `.vwf` file is saved and loaded automatically.

## Standalone Warp Widget

For quick on-site adjustments without opening the full editor, use the **Standalone Warp Widget** (`/warpblend`). This minimal view is optimised for touch-screen control on a tablet.


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