[dsr]

This will seem like an obvious question if we have missed something, but is there any way to know the front and back of the focus zone in Rhino?
Unlike other modeling programs with which we have worked, the Rhino camera only seems to indicate the target point (focal distance), picture plane (focal length) and camera position.
One would think that the camera would also display the focus zone, no?

Any help? Additional plug-ins?

Thanks,
dsr

[JDHill]

It depends what you mean by "display the focus zone" -- if you enable the plugin's Camera Heads-Up Display, the plugin will indicate the near/far DOF values, given the current focal point and fStop.

[dsr]

We know about the Heads-Up Display, but a few things about it do not make sense.
First, it does not automatically update when you change the fStop (and/or other related) settings.
It will update if you de-select and select it, but this is cumbersome.
Second, and most importantly, it gives negative numbers for the "far" distance. How can that be? What does that mean?
Finally, it seems like a simple graphic display on the camera would be a lot more useful. Otherwise, you are left to measure and calculate manually what is and what is not in focus.
This cannot be the way most folks are working? Especially since most other cameras on similar programs display the front and back focus limits along with the camera automatically.
This is such a serious drawback that there must be another way this is intended to work?

Thanks,
dsr

[JDHill]

Thanks, I hadn't noticed it wasn't updating with fStop changes -- I'll fix that. As far as the numbers go, these are just what I figure mathematically for the given inputs, based on generally-available lens equations. I will look into printing "infinite" for certain value combinations. I am not clear on what you are referring to regarding displaying focus limits; could you be more specific? For instance, Studio displays a red/blue focus reticle -- Rhino has a good display API, but I'm not sure if it would be possible for the plugin to do something like that. As for how most people work, I assume Maxwell Fire would be the main tool used here.

[dsr]

So the negative numbers occur because the far limit goes to infinity? Is this correct? And any negative dof(f) can be understood as infinite?

As far as the dof range (near to far), we are looking to find an easy way to see this graphically as part of the camera display. If would be a similar graphic to one showing the near and far clipping planes. In true plan this would be two lines perpendicular to the camera/target center-line that stretched from on fov angle line to the other. The line closer to the camera would represent the dof (n) and the other line would be the dof (f). In between, the camera would be in focus. In perspective, the two limits would be represented by planes.

With regard to Maxwell Studio, we would rather not have to use it just to set and adjust the camera focus. We could use Fire, but that is not all that clear with complex scenes. Perhaps you are suggesting that we simply the scenes (i.e. use only primary objects and/or layers) when we set the camera focus for each scene? That is a possibility, but, again, we would rather just see a graphic of the range that is in focus in a plan view as that seems a much more accurate and efficient way to control focus.

Thanks,
dsr

PS. Are you writing the entire Rhino-plugin? I should probably know this, huh?

[JDHill]

Regarding negative numbers vs. infinity, I can't say yet -- this information (DOF numbers, near/far/etc) is neither a part of the Rhino camera, nor the Maxwell one, and is all derived from geometric aspects of those two, by the plugin, just for display in the HUD. So I have to look into what it means, exactly, before I could say; the term is often associated with a subject being at or beyond hyperfocal distance, but the usage in this context is slightly different.

On the display suggestion, In think I have the gist, and I'll see what I can come up with. Your comments, though, illuminate an important factor: parallel views are really not suitable for precision work in the plugin. Maxwell has no parallel projection, so support for these is only by means of a super-long lens hack (just export to Studio and take a look one of these cameras, comparing it with Rhino's viewport representation, to see what I mean), the implementation of which results in your loss of control over various aspects of the camera. Parallel view approximation is provided more or less as a convenience, and if you wish to retain real control, the only option is to use a perspective view with a similar long-lens strategy, created and managed manually, with the understanding that since Maxwell lacks a parallel projection, it is not possible to obtain a perfect match with a parallel view.

On your PS, yes, I am the author of this plugin.

[dsr]

I think I might have confused the issue by referring to a top view vs. a perspective view. I did not mean to suggest I was after a parallel view. Rather, I would like to see the camera in a top view that was set up to render another perspective (not parallel) view (normal lens focal lengths). Conceptually, you could view this camera in another non-rendered perspective view that would show the camera, associated focus planes, etc. and that view would have the focus planes in perspective. Again, the view I am thinking of is very similar to what the camera looks like when you can see the front and back clipping planes.

Does that clarify anything?

Thanks, by the way for a great product!

Best,
dsr

[JDHill]

Yes, and thanks for the suggestion, pretty sure I have a decent handle now on what you're looking for.