DIGITAL COMPOSITING: Camera mapping in After Effects

Camera Mapping, as discussed in a previous tutorial is a method for creating a rudimentary 3D scene from a 2D photograph. We already looked at using 3D Studio Max to recreate geometry before projecting our photo onto it, but for simpler photographs there are a few methods that can be done with just After Effects and Photoshop alone.

We will use this photo:

corridor-007-a2uadotcom

AFTER EFFECTS PLANES METHOD

1: Import your photograph into After effects. Create a new Camera also, With Layer > New > Camera.

2: Create a New Solid Layer, coloured pure White (So projected colour from the photograph is not tinted later).

3: Add a grid effect to the solid layer, and set it to be a 3D layer in the Timeline. Now set its anchor point to be 0,0,0, then position and rotate it in space so that it matches one of your perspective planes in the photograph. This is a fiddly process, but the grid lines will make this easier.

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4: Duplicate the layer and reposition it to cover another part of your photograph. With the anchor point at 0,0,0, you can simply rotate it 90′ to make a floor a wall, then scale it up or down to cover the right area. Duplicate and move to make the opposite wall etc. When finished, your scene should look like this:

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To check the positions of your layers, you can use the ‘Unified Camera Tool’ by pressing ‘C’ or clicking the icon in the toolbar. This lets you pan around the 3d scene to see how your 3d layers are positioned with each other. To reset the camera view, open it’s transform property in the timeline and simply click ‘reset’.

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4: Now we have our Rudimentary 3D scene created, we need to project the photo onto it. This works similarly to a film projector projecting light through a screen – so what we want to do is create a new Light with Layer > New > Light. The type we want is Spotlight – Once again we want this to be pure white in colour, but we also want it to cast shadows, so make sure that option is checked. Rename it ‘Projector light, so we dont get it confused with any others we may add later.

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5: Next we need to reposition this to exactly where our camera is. To do this, open the cameras position property in the timeline, highlight and copy it with Ctrl + C, then paste it onto the light.

6: Make the initial Photo a 3d Layer, then move it just a few pixels in front of the camera, then scale it down so it once again matches your grids. Now in its timeline properties, In Material options, click ‘Casts Shadows’ twice, so it is set to ‘Only’ Then set Light Transmission up to 100%.

7:Our screen may suddenly go black! Thats not a problem – the last thing we need to do now is set our white ‘grid’ layers to accept the projection. First off, hide the grid effect – it’s job is done. Now in it’s material options, set the ‘Accept Lights’ option to ‘Off’. You will see the effect finally working!

8: Now simply keyframe some animation onto your camera, and you will see the parallax effect we were aiming for. You can also add other 3d layers such as text or green screen elements into the scene and positioning them in z space.

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9: You may notice your image is fairly low quality now it’s been projected. We can improve this by going to Composition > Composition Settings then clicking the Advanced button. From Here, Click the Renderer Options button, and in the shadow map dropdown change the value from ‘Comp size’ to a higher value. Note that this will negatively impact render times.

 

 

PHOTOSHOP VANISHING POINT METHOD.

This method is remarkably faster forgoing the need to play with lights and shadow settings etc. NB – This is only available in PHOTOSHOP EXTENDED VERSION

1. Open your image in Photoshop. For this example, I choose a picture of a corridor from a2ua.com receding to a single vanishing point.

2:Go to filter – vanishing point to open a new window.

3:With the Create Plane tool Selected, Click 4 points to make a perspective plane, eg the floor.

4: Ctrl + click an edge to drag it up as a wall.

Once you have gridded the whole room, including the cieling/sky and back wall DO NOT click OK. Click the tiny little Menu button beside the toolbar, and choose ‘Export for After Effects (.vpe)’. NB This is only available in Photoshop Extended (sad face)

5: Save your VPE file and import it into After Effects. It opens a new comp, which is a series of jpegs, a camera and a parent null. Straighten out the image if it is wonky. It is already set up as a 3d room, so you can zoom in and out.

Compared to the previous method, this one takes out a lot of the fussy work, even if it does require the extra software!

6: Fix your composition settings, eg to HD resolution. You can now add text or other elements, set as 3D Layers.

You can also add DOF for a bit of realism. Open camera options and adjust focal distance and aperture up.

Vanishing point will also work for 2 point perspective – just create the extra planes to cover each portion of the image.

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