Camera Matching in Six Steps in 3ds Max
3ds Max and other software usually have a plugin to help the user with camera matching. I think it is also important to know the basic perspective rules to make a perfect camera match quickly and manually. In this tutorial I'll be using 3ds Max, but this is an universal technique than can be applied to other software packages too.
I'm supposing that the picture I want to match was taken on the ground by a 1.70m tall man, as this is the most common average height. Here's the original image, so that you can work through the exercise yourself (Fig.00).
Let's get started!
In the render panel (F10) set the render Output Size and then put the image as the background. They must have the same image aspect. Our picture is 1600 x 1200 (= 1,333 image aspect)(Fig.01).
Select the picture as the background (Fig.02).
Be sure to use Show Safe Frame for the camera view (Shift + F) in order to display the correct proportions in the viewport (Fig.03).
Create a plane, like a big floor, and set up lots of subdivisions. These lines will help us to match the camera with the plane more easily (Fig.04).
Create a camera and set Camera and Camera Target to 1.70cm height (the same height we are assuming the picture was taken from). Then set the camera in a viewport (Fig.05).
This picture was taken from the ground and this means the horizon corresponds to human height. So activate Camera Horizon, then select and move Camera Target along the Z axis to match the virtual horizon to human height (= real horizon)(Fig.06 - 07).
Set the camera focal length (Lens) to the real camera focal length (Fig.08). There are three ways to know the focal length in the picture:
- You already know it because you took the photo and you know your camera
- Right click on the picture. You can find this value in Advanced Properties
- Just experiment! It's usually around 35-38mm.
Move the camera target right and left until it matches the lines (Fig.09)
If you want to test your camera match you can do two things:
- Move the plane up and down and check if it matches the photo
- Delete the plane and create objects in the scene: they must look like they're a part of the picture (Fig.10).
In this video you can follow these six steps in three minutes!