Often wondered about this.  If I want a close up of something small, such as a guitar pedal, it takes forever to render it big enough to fill the screen.  If, however, I enlarge the thing to 1000%, pull back the camera, it renders significantly faster?

Anyone know why?

Most likely since the vertexes are spread out (by enlarging) it takes less computing to figure out where a surface is and if it interacts with another surface.  But that is just a guess.  Also the scale between the background and the object are closer together.

Makes sense about the vertices.  Not sure about the background, since when I'm doing these renders they're usually in an empty scene.  No background, no images or anything else.  I was making some images to turn into library icons.

Anyhow, I'm happy that it does the trick for whatever reason but I was - and still am - curious about it.

I do not know about Poser internals, but other (older) software used octree culling, which is a binary search in 3d, in each step it examines all the cubes, and tosses out all with nothing in them.  a small object takes more levels to find which cube(s) the object occupies 

https://en.wikipedia.org/wiki/Octree

Bill

Makes sense up to a point but Poser tends to render very fast when there's nothing in the bucket to do anything with, regardless of object size.  It'll slow to a crawl on the object surface but as soon as it goes past... zooom.

If this is Firefly you're talking about, Sam, I'd suspect a maths underflow of some kind. Firefly was bought in for Poser 5, and I dimly recall there were some artifacts which could be minimised by scaling up the scene before rendering. The theory was that Firefly hadn't been properly optimised to work with Poser geometries, which tend to be many times smaller that those found in the majority of the 3D world. The problem was fixed in Poser 6 but I didn't see an explanation of what was done.

I've never had cause to render something small on its own, but now I have to try the experiment for myself. :)

I think it has something to do with the textures. You are asking the 3d program you are using to bend, change the texture image according to a given shape, the shape of your object. Try an up close render of the object without any texture applied. See how fast that is.