What setting should I make (before I start to sculp a portrait head) if I’m planning to 3D print the portrait head later? Everytime I tried to find the right settings (ortho, perspective, camera angle, focal length) it never worked. The 3D printed stuff always looked different than what I see on the laptop screen. When I set the focal lenght to 30 mm then the zbrush perspective view is good on screen, but when I print the model it looks bad… looks like more ortho.
Hello @ZBrush888 ,
There are no “right” settings. There is no 1:1 relationship between camera (digital or otherwise) and human optical reality. They are two different things. There are however different opinions on which focal length/fov most closely resemble the other.
The default focal length setting of 50mm is often said to be most equivalent to human vision. Others may say 35mm. But there are many variables involved. You will need to do some reading and form your own conclusions.
Re: Ortho perspective is a very useful tool for modeling and establishing proportion. However, it is a lie, visually speaking. You shouldnt keep it on all the time so you don’t train your eyes to get used to looking at the model that way.
It is though an invaluable tool for establishing proportions, which can be established to a mathematical degree of certainty. If your model is proportionally correct, then it will be correct in whatever manner you view or print it. Physical features have a quantifiable size relationship. If one cylinder is exactly half the length of another cylinder and it is modeled that way, then those two cylinders will be correct no matter how they are viewed. They will be correct at any size they are printed at.
So it may be that your proportions are off. This becomes more of an artistic discipline and has been heavily studied for centuries. You’ll be able to find quite a few resources devoted to human proportions and anatomy. Both the camera and the human eye are capable of distorting reality under different viewing conditions. The only way to make sure your model is actually correct is to ensure that it is proportionally accurate.
I might recommend switching perspective mode off in the early stages of your model to establish the correct proportions. Then turn it on and leave it on unless you need to be able to achieve a specific result with an operation, for instance accurately “selecting through” the geometry with a selection marquee. Keep in mind that no matter what your camera settings, while you are working in the program you are working extremely close to the model–closer than you would be viewing it in reality. This will cause it to look different. So be sure to zoom out and also view it at the approximate distance and angle you’d be viewing it in real life.
Finally, I’d just point you to the Universal Camera documentation. Be sure to familiarize yourself with Auto-crop mode, as it can alter the experience when working very close to a model:
http://docs.pixologic.com/user-guide/3d-modeling/modeling-basics/perspective/universal-camera/
Thanks. I’m not sure I understand you. So when the perpective button is off, then I see my model in orthographic? Orthographic = without any imitation of distortion = exact mathematical proportions? So I need to start the modeling in orthographic (perspective off)? And when the proportions are correct, then I can zoom out and turn the perspective view on with 35 mm distance which is something like I would hold a 3Dprinted action figure in my hand as I look at it (my hand and my eyes distance as 35 mm)?
Correct. If you switch off perspective you are viewing the absolute dimensions of the model without any foreshortening. This is useful for making sure that points on the model have the correct absolute relationship to each other. Adding perspective distortion will make this more difficult as it may alter the appearance of the location of the points. If you need to establish a specific size relationship with the features on the mesh, it is best to check it in this mode.
Please see the following image. On the left I’m viewing the feet of the demosoldier model with perspective OFF. It shows the actual dimensions of the model. The feet have a certain size relationship to the rest of the model and that relationship does not change.
This is physical reality. However this can only exist in the digital space. It does not represent how the physical object will actually look. Our eyes process information with perspective.
On the right is with perspective is switched on. Depending on the viewing angle, this now distorts the proportions to simulate the way it would look in reality. However, the physical relationships are no longer consistent. Depending on your viewing angle and distance, you might think the feet were actually much larger than the body.
This is optical or camera reality.
It’s mostly how I work. Your mileage may vary. However I emphasize getting the proportions correct and don’t worry overmuch about any particular setting. There are simply too many variables that affect the way a model will look in reality.
One additional factor I’ll make you aware of is the focal center for the perspective mode, which can change the appearance of the model depending on where it is on the canvas. Do as I have done with the demo soldier in that image, and position the feet toward you with perspective mode ON. Then pan the model around the canvas. You’ll see that the legs appear to change the angle they are sticking out at depending how far they are away from the center of the canvas. This is determined by the center of the canvas document, not the center of the viewport. So if your document is partially off screen, this can affect the skew of the model when Perspective is on.
You can actually deactivate this by switching off the Universal Camera in the Draw palette, and using the Legacy Camera instead. When you do, the “Align to Object” feature will become available. This is also sort of a cheat, but it will enable perspective as if the model is always being viewed from the center no matter where it is on the canvas. There is foreshortening, but the 'skew" of the model will not change.
I hope that’s helpful.
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Yes, helped me to get a better understanding. Thank you!