Ways around vertical shift distortion.

[aflack]

I'm just starting an image of an atrium and while I want to use roughly this viewpoint I don't like the squashed top heavy distortion the vertical shift feature applies in Vray.

 

It kind of squashes everything at the base of the image and stretches everything at the top.

 

Is there anyway to get around this that anybody uses?

 

Maybe doubling the size of the view and then cropping it down or something?

 

Is there a way in the viewport setting that I can set the viewport to much larger yet only render a smaller window within it?

 

Thanks

[Chad Warner]

I remember someone mentioning that the method they used was to basically keep your camera and target level, and then back up a long ways until you get the view you were originally looking for. Then you "crop" render your viewport, rendering only the portion you want. That way, you'll have true vertical lines.

[odouble]

Search tutorials @ area.autodesk.com for Exterior Scenes Part 1 – Composition & Cameras

 

you should be all set

[Jeff Mottle]

You should be able to render two shots (keeping the camera level) of the top and bottom of your desired final view and then stitch them together.

[Jeff Mottle]

I'm not sure how the v-ray camera is set up, but when you use a real shift lens, you can take one shot, shift the lens (not tilt) and take another shot to see more in one direction without actually moving the camera, then stitch together.

[moshenko]

I'm just starting an image of an atrium and while I want to use roughly this viewpoint I don't like the squashed top heavy distortion the vertical shift feature applies in Vray.

 

It kind of squashes everything at the base of the image and stretches everything at the top.

 

Is there anyway to get around this that anybody uses?

 

Maybe doubling the size of the view and then cropping it down or something?

 

Is there a way in the viewport setting that I can set the viewport to much larger yet only render a smaller window within it?

 

Thanks

 

I think your only option is to use the blowup feature of Max which allows you to render outside the viewport with no distortion. You'll have to set your blowup region to be the exact same size as the full viewport but "shifted" up out of view. You will have to experiment with how far up to move your blowup region and you will probably have to manually enter values in the region parameters (Viewport configuration -> Regions) to make sure that the two renders match up. I haven't done this in a while but I know that there are scripts available to help with setting values. You should be able to raise your blowup region as much as you've raised your camera target. The major disadvantage of this method is that it is not network renderable using Split Scanlines, if that's what you're after.

 

I think if you're using OpenGL for viewport display you can set a "virtual viewport" that is larger than your "actual" camera extents. I've never tried this but it sounds fun!

[johnvid]

In Vray it would be the physcam verticle shift, there is a camera correction modifier, i think for normal cameras, it could always be done in photoshop, but the larger the image the better.

[Ian P]

This will sound ridiculous but it think the compostion you have looks great, I reckon alot of the distortion is an optical illusion caused by that shadow on the left, I think without that it would look fine, the verts are straight as is.

 

if you can't live with that the best way as mentioned Before is probably to keep your target and camera level as this will always have straight verts but you'll have to pull back then crop back in, the vray camera shift should be doing exactly the same as a real shift lens so if its good enough for the photographers its good enough for me.

[moshenko]

I think your only option is to use the blowup feature of Max which allows you to render outside the viewport with no distortion.

 

Note: I think I'm wrong about this after doing a couple of quick tests. If you try this method please post your results.

[artassoc]

I use the skew modifier on the cammera (not the target) to shift my view. I keep my cammera and target level with each other and add two skew modifiers, one to shift my view horizontally; the other one is set to 90 degrees and shifts my view vertically.