yafaray camera and blender internal camera

I have recently started using yafaray for rendering. I wanted to try a compositing method by using both renderers and combining renders

The problem is that the objects have different sizes and thus won’t line up. I was wondering if there’s a setting to fix this or a technique?

I’m not sure I undestand what you want to do, can you explain it better? what render engines you want to use together?

I wanted to mix together two renders of the same scene, one from yafaray and the other from blender internal.
Basically i wanted to see if i could test a lighting idea i had.
Using the yafaray render for lighting and using the colour render layer from blender internal i wanted to mix the two together.

This really spawned from me not likeing the fact that my material settings in blender were not taken to yafaray

so does anybody have any ideas?

Is the camera the same in vray or one of the others or is there someway to fix the problem of a scene rendered in internal not matching the proportion and scale of a yafaray render of the same scene.

can you post an example of that issue you comment?

http://img50.imageshack.us/my.php?image=policerendercomparedi8.jpgsorry for the late post but here is an example of what i mean.

http://img50.imageshack.us/img50/5994/policerendercomparedi8.th.jpghttp://img50.imageshack.us/images/thpix.gif
http://blenderartists.org/forum/img=http://img50.imageshack.us/images/thpix.gif%5D%5B/url%5D

the car in the background was rendered in blender internal and the car layered on top was rendered in yayaray. See how they don’t match up even though they are from the same scene.

See my question is how do you make the two line up perfectly?

The Blender camera has too small a lens size, and is distorting the image.

In blender i have tried changing the camre lens to fit the yafaray one but it still wouldn’t work.

Does anyone have any suggestions?

Are both cameras the same type?
Maybe you have the Yaf(a)ray one set to architect and the Blender one perspective, or some other combination?

the yafaray camera is set to perspective with an aperture size of 0.

The blender camera is set to perspective with a lens of 35 or 49.14 degrees.

I don’t know if that helps.

But still if anyone has any suggestions on how to match the two.

I can’t replicate the result you are getting, both images are identical in terms of scale and proportion.

Are you using nodes?
Can you post a .blend, or is the work commercially sensitive?

no i’m not using nodes.

organic when you say that both images are identical in both scale and proportion are you referring to mine or your own personal test?

At the moment i am uploading the .blend for you organic and anyone else.

Just remember that if anybody has any suggestions to help me out, it would be much appreciated.

here is the .blend file for anyone interested.

http://www.megaupload.com/?d=S8PX0K89

I think the aspect ratio setting for the Blender camera is causing the distortion. I’m guessing this is not exported to Yaf(a)ray, hence the difference.
Which render preset are you using?

EDIT - Sorry, I mean the aspect ratio settings on the Blender render panel.

Here is a quick composite of the two renders:-

well i actually did export to yaf(a)ray with the python script and the aspect ratio was 800 x 600.

Organic wouldn’t the setting for aspect ratio be the same when you export to yaf(a)ray?

600 x 800 is the image size, below that is aspect ratio. At 64 x 45 pixels are taller than they are wide so the Blender render appears stretched. If that information isn’t exported then Yaf(a)ray will render with square pixels, so the images don’t match.
From the wiki:-

SizeX, SizeY
The size of the rendering in pixels. The actual value is also determined by the percentage buttons (100%, 75%, etc.).

AspX, AspY

The pixel relationship. The pixels in monitors and video cards are not usually exactly square. These numbers can be used to specify the relative dimensions of a pixel.
http://wiki.blender.org/index.php/Reference/Buttons/Scene_Context

Some of the presets use different ratios if you are rendering for T.V.

Like Yafray, Yaf(a)ray doesn’t have access to all of Blender’s functions.

EDIT - the page I linked to is a long time out of date - ‘This page was last modified 14:06, 10 December 2006’
This is more recent - http://wiki.blender.org/index.php/Manual/Output_Formats#Format_Panel