IRAY Calculating Objects OUTSIDE the Camera View?

Fauvist

If you've got a scene with a hundred objects (human figures, furniture, buildings, etc.), but your camera view only includes 5 objects, such as a close-up of a human figure wearing an outfit and hair and sitting on a chair in front of a wall) - is Iray calculating for just those 5 figures?  Or is it calculating the render based on the 100 figures in the scene but outside the view of the camera?

Havos

Fauvist said:

If you've got a scene with a hundred objects (human figures, furniture, buildings, etc.), but your camera view only includes 5 objects, such as a close-up of a human figure wearing an outfit and hair and sitting on a chair in front of a wall) - is Iray calculating for just those 5 figures?  Or is it calculating the render based on the 100 figures in the scene but outside the view of the camera?

Since those 100 off screen objects could be affecting reflections, or casting shadows etc, then naturally the renderer has to take them into consideration. However it does not need to calculate how that off screen object would look like due to the light hitting it, so I believe a lot of calculations on it are avoided. 

ebergerly

Just make the non-visible objects (outside the camera view) invisible by clicking the eye icon for each object in the Scene tab and they will be ignored by Iray.

However, since in the real world the correct light on the visible, main character objects in the camera view would/should include the light bouncing off those other objects, making those objects invisible makes the lighting on the main character incorrect. 

rsharp_3144816

ebergerly said:

Just make the non-visible objects (outside the camera view) invisible by clicking the eye icon for each object in the Scene tab and they will be ignored by Iray.

However, since in the real world the correct light on the visible, main character objects in the camera view would include the light bouncing off those other objects, making those objects invisible makes the lighting on the main character incorrect. 

Not necessarilly.  There would be numerous instances of counter-examples where the out-of-view objects would either have zero influence, or effecitively zero influence.  It's sometimes all about cheating to decrease render times.  For example, if you find that you don't get some nice details when hiding the off-screen stuff, create a plane with a simple texture to approximate the out-of-view objects.

ebergerly

rsharp said:

Not necessarilly.  There would be numerous instances of counter-examples where the out-of-view objects would either have zero influence, or effecitively zero influence.  

Obviously. 

 

nicstt

Fauvist said:

If you've got a scene with a hundred objects (human figures, furniture, buildings, etc.), but your camera view only includes 5 objects, such as a close-up of a human figure wearing an outfit and hair and sitting on a chair in front of a wall) - is Iray calculating for just those 5 figures?  Or is it calculating the render based on the 100 figures in the scene but outside the view of the camera?

How does it know what to include in reflections?

How does it calculate how light interracts with objects?

Whilst an object might have little impact on the image, it is only by calculating the light bounces (and whatever else light does) that the render engine determines the final image's composition.

Fauvist

How does Iray deal with infinite space?  Like when there is no skydome or ground plane?  Like when you want the background to be transparent in the final render?

kenshaw011267

Fauvist said:

How does Iray deal with infinite space?  Like when there is no skydome or ground plane?  Like when you want the background to be transparent in the final render?

Depending on settings you get either a pure black background or a gray one. IIRC infinite usually gets you the gray.

RobotHeadArt

Iray does have to take objects out of camera's view into account.  More importantly, all visible objects in the scene and their associated textures are loaded into GPU memory or convential memory for CPU rendering.  Some 3D tools and render engines allow for camera frustum culling which actually hides the geometry outside of the camera's view thus reducing resources needed by the renderer but it is not available in DAZ Studio currently.  https://en.wikipedia.org/wiki/Viewing_frustum

Mattymanx

All items in the scene and their textures ARE loaded into VRAM by Iray when you render, even if its not seen.  So if its not going to be seen at all, either turn it off in the scene tab or delete it from the scene!  If you do need them in the scene and you need to cut back on resources, I would recommend this - https://www.daz3d.com/resource-saver-shaders-collection-for-iray

ebergerly

Fauvist said:

How does Iray deal with infinite space?  Like when there is no skydome or ground plane?  Like when you want the background to be transparent in the final render?

If there's nothing for the rays to hit it will render as transparent. However, you also need to make sure you save the render in a 32 bit format that includes an alpha channel or else it won't be transparent. 

fastbike1

@RobotHeadArt "Some 3D tools and render engines allow for camera frustum culling which actually hides the geometry outside of the camera's view thus reducing resources needed by the renderer but it is not available in DAZ Studio currently."

Iray Section Plane will accomplish the same thing.

RobotHeadArt

fastbike1 said:

@RobotHeadArt "Some 3D tools and render engines allow for camera frustum culling which actually hides the geometry outside of the camera's view thus reducing resources needed by the renderer but it is not available in DAZ Studio currently."

Iray Section Plane will accomplish the same thing.

Actually the Iray Section Plane does not do real culling.  The geometry and materials still consume memory.  I just verified this by rendering a scene, once with the Iray Section Plane hiding 100% of the geometry and the other with the Iray Section Plane disabled.  Both used exactly same amount of GPU RAM.

xyer0

Mattymanx said:

All items in the scene and their textures ARE loaded into VRAM by Iray when you render, even if its not seen.  So if its not going to be seen at all, either turn it off in the scene tab or delete it from the scene!  If you do need them in the scene and you need to cut back on resources, I would recommend this - https://www.daz3d.com/resource-saver-shaders-collection-for-iray

You beat me to it, Mattymanx, and thanks for making my 3D life a LOT simpler.

I've taken to DELETING everything off-camera except those items that cast a PARTICULAR shadow. I have various emissive and reflective objects off-camera surrounding the subject to add interest. Of course, first I save a version with everything.