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DHudson
08-03-2006, 08:06 AM
Hello-

I have been working on this room for a while to display a client's wood mouldings. The angle at top and bottom of the moulding on the right side of the columnar wall should be at the same angle, shouldn't they?

I can't seem to fix it with the camera angle. Is there a fix here? It would be parallel in real life, why can't I make it here?

Also - I want the background moulding to be a bit more fuzzy. I have the DOF focal distance set at 32.2 m (just to the back tip of the fore moulding), with the lens f-stop set at 2.75.

Thank you in advance for any help!

Penforhire
08-03-2006, 11:23 AM
Can't help with the first question but I have some recent frustrating experience with DOF. :)

You may need to go even lower in f-stop. The number has little connection to the results you expect if you know photography. Have you activated DOF and are you rendering with at least Medium AA (less than that will not implement DOF in the render)?

DHudson
08-03-2006, 11:31 AM
Yes, I have DOF check marked and I am using enhanced medium AA. I was reading through Don Ablan's 'Inside LW8' book, and followed his suggestion of adding a null in order to get "Range Finder" set up. I did this. Still to no avail.

help help!

gjjackson
08-03-2006, 11:56 AM
I know I've seen this done. It was done with some type of camera technique. I haven't had a need for such a camera view so I can't remember how it's done. It seems I seen it in a video.

kruemel_1
08-03-2006, 12:12 PM
to the first question: no they shouldn't. All Lines in perspective projection are projecte towards a point, so parallel lines have in perspective an angle. To get parallel lines you have to use the ortho camera (parallel projection camera).
To the second question: try a very small f-stop value (below 1.0). 32.3m seems to me a long focal length for this detail, with a pocketcam i would suppose the picture taken from 1-2m .

DHudson
08-03-2006, 12:19 PM
kruemel_1 thank you so much for your answers! Could you tell me about the parallel projection camera? Where is it? Will it ruin the other correct angles?

And is what you are saying is that the top and bottom of the mouldings should NOT be parallel in real life?

Tzan
08-03-2006, 12:27 PM
And is what you are saying is that the top and bottom of the mouldings should NOT be parallel in real life?


What do you mean by real life? :)

When its constructed in a house and in a 3D model the top and bottom edge are the same distance apart at each corner.

When viewed in real life or a LW camera with a normal perspective set you will see an image like your post above. The top and bottom lines converge to a single vanishing point in the distance. This is normal.

You should Google for a site that has a tutorial for perspective drawing.

kruemel_1
08-03-2006, 12:38 PM
The Parallel projection camera is called "Ortho Camera" in LW 9. There you can switch the cameratype in the camera settings. With LW 8.5 and earlier you have to "fake" it by using a very far camera (1km or so) and a high zoomfactor. So you get a nearly parallel projection.
Parallel projection means all parallel lines on the model would also be parallel on the image, there is no "shrinking with distance". It will look like a CAD-Isometric drawing, but with textures :)

DHudson
08-03-2006, 01:02 PM
It's horrificly hot here, so please excuse my adled brain and let me make sure you are saying what I think you are saying ...

If I were to walk through a house, enjoying the wood mouldings, the angles I've highlighted in the attached picture would be correct?

DHudson
08-03-2006, 01:07 PM
Sorry- here's another photo.

kruemel_1
08-03-2006, 01:14 PM
right, that's what i said.
Wikipedia has an artikel about this (and corresponding) phenomen:
http://en.wikipedia.org/wiki/Linear_perspective
Depending on where your camera is you have the one- two or three point perspective.

DHudson
08-03-2006, 01:17 PM
kruemel_1 - thank you again for your thoughts, could you tell me, when you say "a very far camera (1km or so)" - what am I adjust here? The pixel aspect ratio?

kruemel_1
08-03-2006, 01:31 PM
You have to set the focal length also to a very high value. Pixel aspect or resolution has nothing to do with it.
But I suppose with a parallel projection you won't get a DOF effect. Simply because you can't set this small value for the f-stop.

DHudson
08-03-2006, 01:37 PM
So I can't have a fuzzy background AND use this trick with the camera (since I have LW 8)?

kruemel_1
08-03-2006, 01:45 PM
I suppose so. You can try it with a f-stop 0,001 or lower, but you shoudn't be surprised if it isn't working.

iconoclasty
08-03-2006, 01:56 PM
In hopes of finding a solution that will work for you can I ask; why do you want the angles parallel? The render you have seems perfectly accurate for a perspective view of your molding.
If you tried the far off camera trick and got the top and bottom of the molding more parallel then it would look strange.

Tzan
08-03-2006, 03:04 PM
If I were to walk through a house, enjoying the wood mouldings, the angles I've highlighted in the attached picture would be correct?


Yes.
Just look at some bookcase, all the shelves are at different angles.

The image you made is fine, you dont need to change the perspective.