# How to use the results You can use environment maps in various ways within Unreal Engine, depending on the results you want to achieve. Each method serves a specific purpose and can enhance different elements of your scene. Here are the most common use cases of environment maps: ## HDRI Backdrop ### Overview The **HDRI Backdrop** Actor enables you to showcase a model in a visually rich context with minimal effort, and using a High Dynamic Range (HDR) image as a backdrop, improving your product visualization workflow\.It's relatively quick to set up, it's customizable, and provides beautiful illumination and reflections. It automatically handles the following: * Background mesh (such as a sky dome or custom geometry) * Ambient lighting from a Dynamic Sky Light * Dynamic reflections * Ground projection with shadow catching {% hint style="info" %} If you can't find the HDRI Backdrop Actor, make sure you have enabled the **HDRI Backdrop** plugin in your project! {% endhint %} ### Setup 1. In the **Place Actors** panel, click and drag the **HDRI Backdrop** asset into the **Level Viewport**. 2. With the HDRI Backdrop asset selected in your level, use the **Details** panel to set the following: * **Cubemap:** Choose your cubemap from the available options or drag one from the **Content Browser** onto this slot. * **Size:** Adjust the value here to set the size of the mesh that the HDR image is being projected onto. * **Projection Center:** Select the 3D gizmo to move the projection center to match your camera placement and adjust as needed to reduce skewing and stretching of the HDR image on the backdrop. Optionally, add a **Light Source** and set it to **Movable** if you want dynamic shadows in your visualization. {% hint style="warning" %} Using an HDR image as a background is not sufficient on its own. For the result to be plausible, there needs to be a fake ground plane that acts as a shadow catcher to ground the object in the HDR image's environment when being lit, creating consistency between the place object for visualization with the background. {% endhint %} \ You can find more useful information about HDRI Backdrop setup on the official UE documentation: {% embed url="" %} ## Skylight ### Overview The Sky Light captures the distant parts of your level and applies that to the scene as a light. That means the sky's appearance and its lighting/reflections will match, even if your sky is coming from atmosphere, or layered clouds on top of a skybox, or distant mountains. You can also manually specify a cubemap to use. ### Setup 1. In the **Place Actors** panel, click and drag the **HDRI Backdrop** asset into the **Level Viewport**. 2. With the Skylight Actor selected in your level, use the **Details>Light** panel to set the following: * **Real Time Capture** -> **false** * **Source Type** -> **SLS\_SpecifiedCubemap** * **Cubemap ->** Choose your cubemap from the available options or drag one from the **Content Browser** onto this slot. You can find more useful information about Skylight setup on the official UE documentation: {% embed url="" %} ## Sphere/Box Reflection Capture ### Overview **Reflection Capture** Actors are probes that can be placed around the world to capture a static image of the area they cover. This reflection method reprojects the captured cubemap onto surrounding reflective materials. It is a low-cost method of reflections with no runtime performance cost. ### Reflection Capture Shapes There are currently two reflection capture shapes: sphere and box. The shape is very important because it controls what part of the level is captured into the cubemap, what shape the level is reprojected onto in reflections, and which part of the level can receive reflections from that cubemap (area of influence). #### Sphere shape The sphere shape is currently the most useful. It never matches the shape of the geometry being reflected but has no discontinuities or corners, therefore, the error is uniform. #### Box shape The box shape is very limited in usefulness and generally only works for hallways or rectangular rooms. The reason is that only pixels inside the box can see the reflection, and at the same time all geometry inside the box is projected onto the box shape, creating significant artifacts in many cases. ### Setup 1. Navigate to the **Place Actors** panel and in the **Visual Effects** tab, select and drag a **Sphere Reflection Capture** Actor to the Level. 2. Select a **Reflection Probe** Actor that has been placed in the Level and in the **Details** panel under the **Reflection Capture** section change the **Reflection Source Type** from **Captured Scene** to **Specified Cubemap.** 3. With the Reflection Probe still selected in the Level, go to the **Content Browser** and select the HDRI Texture you want to use. Then in the **Reflection Capture** Actor, under the **Reflection Capture** drag the HDRI Texture from the **Content Browser** to the **Cubemap** input. 4. Click **Build** on the **Main** menu panel and select **Build Reflection Capture** to use the new HDRI Cubemap Texture that was just specified. You can find more useful information about Skylight setup on the official UE documentation: {% embed url="" %} ## Post Process Volume - Ambient Cubemap ### Overview Post-processing effects enable artists and designers to define the overall look and feel of the scene through a combined selection of properties and features that affect coloring, tonemapping, lighting, and more. A special type of volume, called a **Post Process Volume**, can be added to a Level to access these features. ### Setup 1. In the **Place Actors** panel, click and drag the **Post Process Volume** asset into the **Level Viewport**. 2. With the Post Process Volume Actor selected in your level, use the **Details>Rendering Features>Ambient Cubemap** panel and set your environment map as the **Cubemap Texture.** {% hint style="warning" %} The Ambient Cubemap has limited local shadowing (screen space ambient occlusion only). Use a Sky Light instead when representing the sky's lighting. The Ambient Cubemap is only intended to be used for a subtle directional ambient term (useful in games with completely dynamic lighting), or for model viewer applications. Because light comes from many directions, it cannot simply use shadowmaps for this light type. Screen Space Ambient Occlusion is applied to get contact shadows from nearby geometry. {% endhint %} \ You can find more useful information about Ambient Lighting in Post Process Volumes on the official UE documentation: {% embed url="" %}