Hasta La Motion!

Hello, I am learning camera tracking, but have a problem if u can help. I track the footage, then solve it etc, then set the origin etc, but when i put a test object into the shot, it appears way below the plane, as you can see in the screenshot, is this normal? Also regarding alligning the plane, how do u know it is at the right angle etc, lik when i rotate it can look right at variuos angles in view it from. The screenshot is just an example to show the test objects keep apperaing below the grind plane. I

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