Mirror Offset

Introduction

In a virtual environment, if the floor has a reflective surface, we must properly set up Billboard reflections. General reflections in the scene should be created when you build your scene, however, Billboard reflections should be set up right before every show.
This feature is available for Virtual and Tracked camera workflows as well. In our article, we will discuss the two workflows separately, since there are a few differences between the settings.

Before setting up reflections, you should already have an understanding of the following topics:

- Virtual Cam workflow
- Tracked cam workflow
Setting Up Billboards in Virtual Camera Compounds
- setting up tracked cam billboards

Virtual Cameras

Generally about virtual camera compounds here.

All the below features can be found in the BILLBOARDS control board after you have added a virtual camera compound to your project.

Select the BILLBOARD # panel.

You will find all settings in the Pin Values window on the right side of the screen.

Mirror Offset

The Mirror Offset feature can help tune the position of the reflection if the talent does not move back and forth in front of the camera.

Note: In our general billboard setup document we have already discussed, that when placing the Billboard in our scene, we have to be mindful of the vertical position of the Billboard. Make sure that the Y position of the Billboard is properly set.

Here the reflection of the talent is not placed properly

After adjusting the Mirror Offset

Mirror Feet Blur

When we add a billboard with a talent to our scene, we are adding a 2D image of the talent. If we mirror this 2D representation of the talent, it is different than if we had the talent's real-life reflection. The generated mirrored image is a bit misshaped. This difference can be mostly seen at the feet. To make this less noticeable we can adjust the Mirror Feet Blur.

Mirror Feet Blur turned OFF

And turned ON

 AO can also help cover up these imperfections. Since the AO is not a reflection, we will not discuss it here, but in the document related to billboard shadows. You can find this here.

Feet Blur Offset

With the Feet Blur Offset value, you can adjust the position of the center of the blur of the reflection.
Usually, the default value works well.

Auto Mirror Offset

Another issue is when the talent is moving backward, further away from the camera, the feet will appear further from the bottom of the billboard.

Turning ON the Auto Mirror Offset feature will automatically align the reflection to the talent's feet.

After enabling this feature, Aximmetry will ignore the Mirror Offset value.

The feature works best if the talent takes slow, short steps and does not move very far away from the original position. Also, the feet closer to the bottom of the Billboard will be taken into consideration when calculating the distance, so we recommend trying to keep both feet at the same distance from the bottom of the Billboard.

Tracked Cameras

More on tracked camera compounds here.

Reflections with tracked cameras can only be set up after enabling Billboards. More information on this here.

Mirror Offset Z

Similar to the Mirror Offset setting in virtual cameras you can use this feature to align the reflection to the talent's feet.

Mirror Feet Blur

This will blur the reflection (same as Mirror Feet Blur for virtual cameras).

Blur Depth & Amount

Blur Depth is a percentage, which defines how far from the billboard should the blurring affect the reflection.

Blur Amount is the amount of blur.

Billboard Tracking

With tracked cameras, there is no need for the auto mirror offset feature, since usually the billboard is either tracked with an object tracking device and moves with the talent, or Aximmetry's built-in optical tracking feature can be used. More on these options in the Tracked Camera Billboards: Placement document.

As for both cases, if the Mirror Offset Z setting is properly adjusted, the reflection will be matched to the talent's feet by the billboard's movement.