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View Full Version : What are the xyz rotation angles for rendering ISO objects?

Neyjour
07-17-2013, 04:58 PM
I cannot, for the life of me, figure this out. And absolutely nothing turns up with a Google search (although, that may be because I'm not using the right search words/terms). So I imported an ISO grid background into Poser to try and position an object by eye, but It's just not working. Please help! :?:

Korash
07-17-2013, 06:31 PM
I think that this (http://www.mr-d-n-t.co.uk/isometric.htm)might help. A bit basic maybe, but at least it gets the idea across. Basically, all sides in a basic shape, except the vertical, are at 30 degrees + or - from the horizontal and all vertical lines are 90 degs. Unless of course you are getting into complex shapes without right angles in the shape. Then it gets complicated.....

Midgardsormr
07-17-2013, 07:21 PM
45 degrees in Y and -35.264 degrees in X. (Assuming Y-up software)

You need an orthographic camera for this to work. The standard camera in most 3d packages is a perspective camera, which cannot render truly isometric imagery. You can fake it by moving the camera way back and using a ridiculously long lens, though.

Neyjour
07-17-2013, 07:31 PM
Thanks Korash, but...I don't really think that's going to help for what I want to do. Or, I'm just not understanding it...

What I want to do is render various objects, and I need to know the rotation values for x, y and z. Or maybe it's not even possible to to do it like this, and objects can only be done right if they're drawn?

I've been testing out different pieces and every one seems to have different values to look right (by eye) on the grid. Some are a bit similar, but others are very different. Especially the bridge, which took forever to position...and it still doesn't look quite right to me.

For example, the bridge values are:
xRotate = 28
yRotate = 35
zRotate = 10

And the vine-covered column values are:
xRotate = 33
yRotate = 39
zRotate = 7

The numbers are fairly close for those two, but when I try to match them up exactly, either one object or the other looks really wrong.

And then there's the altar, which has these values:
xRotate = 30
yRotate = 10
zRotate = 10

It's looking like the xRotate is the one that's supposed to be consistently at 30? But not knowing what the others are supposed to be just throws everything off....

Ugh...this is giving me a headache. :?: :(

Neyjour
07-17-2013, 07:36 PM
45 degrees in Y and -35.264 degrees in X. (Assuming Y-up software)

You need an orthographic camera for this to work. The standard camera in most 3d packages is a perspective camera, which cannot render truly isometric imagery. You can fake it by moving the camera way back and using a ridiculously long lens, though.

So basically, it's just not possible to render an object properly for ISO? That's really disappointing. Oh well...

Thanks for the help! :)

Midgardsormr
07-18-2013, 02:17 PM
I wouldn't say "just not possible," but I suspect that Poser's too limited to do it. Flexibility isn't part of its design goals.

I'm fairly sure that Blender permits rendering an isometric projection, for instance. It's possible in 3ds Max, but it's difficult to get the exact rotations since you can't actually select the viewport cameras. Maya makes it pretty easy, since it treats the ortho cameras just like the perspective cam, and you can even select them in the viewport.

As I look at the approach you've been taking, it looks like you're trying to rotate the objects to get the result you want, when what you need to be rotating is the camera. Lay out your scene/map in a physically accurate manner first, without regard to viewpoint. Then you can start looking at where to place your camera and how to configure it for the result you want.

An isometric view eliminates all perspective distortion—the stuff in the back is just as large as the stuff in the front. A camera does not naturally behave this way, but the longer the focal length (higher zoom level), the more perspective gets flattened out. So while you may not be able to get a true isometric render, you can sometimes get something that's close enough, even if you are limited to using a perspective camera. Of course, this depends greatly on the limits of the camera you have. I don't know what the upper limits on Poser's cameras are, but you should be able to at least simulate the longest practical lens on the market, which is 1200mm (they cost US\$120,000, if you're wondering).

Neyjour
07-18-2013, 04:33 PM
I'm not creating a whole map/scene in Poser...just trying to render individual objects that can be saved as transparent PNGs and added to any ISO map.

I tried rotating the camera rather than the object, but that was even more confusing for me, and I couldn't get results that looked even close to being correct. But thanks away, I do appreciate the help. :)

Hai-Etlik
07-18-2013, 07:30 PM
"Iso" in this case is not an acronym. It's from a Greek root and means approximately "the same" or "equal".

That seemingly arbitrary second angle to rotate by of 35.26° is arctan(1/sqrt(2)) and that's important, if you don't rotate by that much, you'll have a dimetric projection.

Chashio
07-27-2013, 04:03 PM
Is there a reason that the objects in your example image are all tilted to the left? What if you just straighten them on the vertical in whatever direction you want to view them from? Sorry. Math is not my forte.

Wordman
09-18-2013, 06:56 PM
Simulating Isometric Cameras in Poser (http://my.smithmicro.com/tutorials/1891.html).

To do isometric, you absolutely must have an orthographic camera. This means, sort of, that the geometry when viewed through that camera doesn't have a vanishing point; two parallel lines will remain the same actual distance apart on screen, no matter how far away from you they go. If you don't have this, you can't "match up" your objects, because for cameras that do use a vanishing point, the rendered geometry depends on the how far the object is from the "lens".

Poser's camera is not orthographic; however, it appears that its directional views (e.g. front, left, etc.) are. So the trick in poser is to use one of those views, then rotate your objects relative to that camera.

Note, however, the settings mentioned in this post are not true isometric settings. The correct settings are mentioned above: 45 degrees in Y and -35.264 degrees in X.