Twilight Render User Forum

I've just set up a view in SU and set the F.O.V to 50mm. Twilight shows the Lens Focal Length (mm) as 34.722mm. If I change Twilight to 50mm the image in S.U. expands off screen and S.U. reports the focal length as 72mm! Is this a bug as the differnece in the renderings is a very slight change in shading?

info

First, we should see about changing your username from being a full email address. (to avoid spam bots hunting it down)

Secondly,
Perhaps this can help you:
To match your rendering to exactly what you see in the viewport:
In the Twilight Render tab, check the Fit to view proportions, then hit the magnifying glass. That's it.
Be sure you have not chosen a particular "camera" in the camera pull-down of the render dialog - if you have, no matter what you see in your viewport it will render that camera. (handy in some cases)
Set it to render "current view" if you want to make sure it's rendering precisely what you see in the SketchUp viewport.

Be careful- the FOV (field of view) and the focal length in the camera tab ARE NOT THE SAME THING! It should be rendering precisely what is shown in your current view. I am, for instance, in a file where my SketchUp field of view is set at 70 degrees (not millimeters!). The Twilight Render Camera Tab reports this as a 17.852mm camera. But the views match perfectly with SU.



http://twilightrender.com/phpBB3/viewto ... 925#p11925
http://twilightrender.com/phpBB3/viewto ... 727#p14727.

I see that, but you can specify the FOV in SU as 50mm (not just degrees), and this is where things start jumping about. Using the camera tab in Twilight to change the camera lens to 50mm changes the lens length is SU to a different value (72mm) & view.

Sorry, I'm probably just being picky due to the unexpected change of view in SU. The final results are both the same. (excellent!)

I've PM'd you about the user name

Are you using the new ACT? (I'm not aware of a way you can easily set the Focal Length in SU...) It's possible there is a conflict with some of the camera parameters, like film height.

Do you have a scene you can post?

Ok, I think I'm on top of this now.

Until now there wasn't a practical way for you to set a camera's "image width" or "focal length". You could do it, but only through a ruby script. Because it was never really changeable, the value displayed in Twilight's camera editor is the focal length based on a 25 mm film width. In SU, if your camera is expecting, say 36 mm (the default value in SU), the displayed focal length would be 72. But in Twilight, using 25 mm film width, the focal length would be 50.

The resulting image, however, is identical.

With the availability of ACT which allows you to set up more advanced camera information, we will probably modify how we display the camera data to maybe include the film width and the associated focal length.

Hi Chris, I'm not using ACT just plain SU.

Easy ways to set focal length in SU...

1. Camera>Field of View enter value in mm's in VCB
2. "Z" (=zoom tool). Type value in VCB in mm's

See http://sketchup.google.com/support/bin/ ... swer=94945 for more info.

AUK wrote:...I'm probably just being picky due to the unexpected change of view in SU. The final results are both the same.

Can you show a screenshot or two demonstrating this behavior please?

Images attached showing...

1. Initial SU screen view set up with SU 50mm lens
2. SU screen view after opening Twilight, clicking on camera tab and changing lens to 50mm

In 2. the VCB still shows 50mm but if you click Zoom in SU the VCB changes to 72mm.

Hope that helps.

AUK wrote:Hi Chris, I'm not using ACT just plain SU.

Easy ways to set focal length in SU...

1. Camera>Field of View enter value in mm's in VCB
2. "Z" (=zoom tool). Type value in VCB in mm's

See http://sketchup.google.com/support/bin/ ... swer=94945 for more info.

Never knew that the VCB would take mm for that! Thanks for the info.

By the way, ACT is free for Pro users, and it looks like it's much easier to use than the standard SU tools for camera manipulation (if you didn't already know that )

I get the same results when setting the FL to 50 mm, I can see 34.722 mm under the TL camera.

However if you do what Fletch or Chris suggested; lock the aspect ratio and use the magnifying glass to scale your rendered image the exact same as your SU model workspace, you get exactly what you see in the SU window.
Maybe that focal length Twilight is reposting initially belongs to the initial, 500 x 500 image? I am a complete idiot when it comes to cameras so just trying...