Photoshop 3D Shadows

Forum|Forum|4 years ago
June 14, 2021
5 replies
2264 views

Just can't quite understand the shadows in Photoshop 3D! I want to place the dinosaur in the upper left corner with a shadow. When the dinosaur is in the lower part of the screen the shadow is there. But as I move it up to the top left the shadow disappears. The attached screen shots show what happens as I move the object up. I sure would like to understand this!

Problem or error

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Correct answer davescm

You are moving your groundplane in relation to your camera (look at the groundplane grid).

First align your groundplane and camera to the photographed scene. The idea is that you use the same focal length and camera position as the original camera used to photograph the scene (e.g. xx feet from the ground, angled at yy degrees and a focal length of 24mm .....etc). In Photoshop this has to be done manually, in many 3D apps there are functions or plug ins for camera matching. Once done leave both camera and groundplane alone, do not move either again.

Next, position your object so that it is standing on the groundplane. Then move your object on the groundplane forwards/backwards and sideways but not up and down. That way you keep the shadow on the groundplane which will show in your scene.

Dave

D

davidc72954600Author

Inspiring

Hi Dave;

Thanks for your comments. I want to get the dinosaur way at the back of the photo still maintaining a shadow. I tried what you said. I positioned the interesection of the blue and red axis and ground plane as best I could. I can't get the interesction of the blue and red axis to the position I want the dinosaur to be in. It just seeems to flip over at one point. I got the shadow at the interesection of the blue and red axis near the front of the photo and then moved the objmesh along the axis towards the back of the photo. That seems to adjust the size of the object (smaller) which is what I want. The shadow does stay with the object but does disappear as it gets near the back of the photo. But it mabe that in the true perspective it wouln't be visible. Please see screen captures.

davescm

Correct answer

Community Expert

You are moving your groundplane in relation to your camera (look at the groundplane grid).

First align your groundplane and camera to the photographed scene. The idea is that you use the same focal length and camera position as the original camera used to photograph the scene (e.g. xx feet from the ground, angled at yy degrees and a focal length of 24mm .....etc). In Photoshop this has to be done manually, in many 3D apps there are functions or plug ins for camera matching. Once done leave both camera and groundplane alone, do not move either again.

Next, position your object so that it is standing on the groundplane. Then move your object on the groundplane forwards/backwards and sideways but not up and down. That way you keep the shadow on the groundplane which will show in your scene.

Dave

D

davidc72954600Author

Inspiring

Being new to 3D objects would it be fair to say that what is happening is not normal? That the shadow should persist while I move it up to the corner? That there might be something wrong with the object?

D

davidc72954600Author

Inspiring

I am using 21.2.0