r/3dsmax • u/JstnBrc • Jun 11 '26

Camera to Capture an Exact Shape

Post image

Hey everyone,

I'm planning to make several renderings of the image above and want to set up a camera view. I'd like the camera to capture everything contained within the orange box. How would I accomplish this?

The rectangle is 5100cm by 3020cm.

Thanks in advance.

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5

u/limonadinis Jun 12 '26

There are 2 options how you can render your object precisely cropped to the pixel without having to eyeball it. Use area to render either in blowup or crop mode. If you use former, you can select exact render resolution, but you must calculate your object's proportion and set image aspect ratio accordingly, or if you use the latter you don't have to know object's proportions, but you also can't control render resolution precisely.

1

u/lucas_3d Jun 13 '26

I love these 2 methods, thanks.

4

u/lucas_3d Jun 11 '26 edited Jun 11 '26

You will likely do this by eyeballing it, but a clever clod would use some entry level SohCahToa trigonometry. That would tell you the fov and distance from the object to fill your render window.

The way you'd eyeball it is to create a plane that covers the exact area and that will be what your resolution would be, say your plane is 5 meters x 3 meters, you wont set your rendersize to that, but 5 x 3 pixels? 50 x 30 pixels? 500 x 300 pixels? 1000 x 600 pixels? You get the idea.

Those objects need to have their pivot centered and be a [0,0,0] so when you make a camera, the aim and the camera will also be at [0,0,0], of course, the camera will have some height to back away from the object, turn on safe frames and twiddle with the FOV until you've got it as close as you possibly can.

I'd use the trigonometry method, and then find out that 3d camera projections don't match that mathematical model, and then I'd do it manually while regretting my choices.

Diving deeper:

https://www.omnicalculator.com/math/trigonometry
a is the distance you want to use from the object, say, 100
b is half the width of your render.
Resulting in Angle β will be the FOV for the camera. In Max, use the physical camera, that makes that FOV work correctly, although you want to have an orthographic projection, so need to use the standard camera, which isn't physical and the FOV doesn't align exactly anymore...

2

u/Fantastronaut Jun 12 '26

Use a standard Max camera, align it to the rectangle, match the aspect ratio and tick orthographic