Projector2UCam

Please note, Unreal Engine integration has changed significantly for Unreal Engine 5.3 and 5.4, so this User Doc is outdated.

Projector2UCam workflow is recommended when every projector needs to project a rendering from a different point of view. Examples of this include very complex 3D objects that need to have projection on most of their faces/surfaces.

This workflow is possible only if projection object exists in Unreal Engine too and the content is applied to it in Unreal as well.

The pipeline consists of the following steps:

1. calibrate your projectors in LightAct. Refer to Projection Mapping chapter for more info.
2. Create .ndisplay configuration file from these projectors in UnrealLink window. This will create one Unreal viewport for every projector. Refer to UnrealLink chapter for more info.
3. Launch nDisplay and Use Texture Share devices nodes to get their textures back.

4. Then you can use Layer Layouts to apply these texture directly to LightAct Projectors.

Due to the nature of this workflow, 3D model in LightAct doesn't have Unreal's content applied to it. It is used only for calibrating the projectors.

Additional Considerations

As this workflow is quite specific, there are additional considerations:

Performance

As every projector generates a separate Unreal Viewport, it means that Unreal is going to have to render the scene from point of view of every projector, which causes a heavy performance load.

Perfect match between real and unreal

Projection object should exist in Unreal

In UE environment, there should only be objects that also exist in reality. Also, the content needs to be applied in Unreal, not in LightAct.

Level of detail

The level of detail of any object in UE4 should match precisely the level of detail of the real model. A typical example are trees which are usually created using complex shaders in Unreal Engine. These kinds of trees usually don't have a perfect physical twin and therefore the projection probably won't look good.

Lighting effects & materials

Any lighting effects that are point-of-view dependent should be eliminated (such as reflections and any kind of volumetric lighting effects).

Particles

Any particle effects, such as smoke, for example, will most likely need to be removed as they are usually not represented in reality.

Additional Help

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