Pigment Pattern Isosurface

I was looking through the "functions.inc" file the other night when I noticed that a function can be based on a evaluating a pigment. I knew you could create a pigment based on the object pattern, so...

I thought it might be possible to create an isosurface that evaluates an object pattern pigment.

A quick question on the news groups and the kind people there told me it would be possible but slow.

So I can now build a complex CSG shape, put it in an object pattern pigment, put that in a function and have an isosurface built to my specs.

But!, you ask , why would you do that if it's slow and you have already buit the shape in CSG? The answer is that I could add noise to the pattern. This might work well for a weathered statue. So I'll be giving this a try in the next couple of days, and let you know how it turns out.

Clipping

Interesting side affect of using the "clipped_by". I had an object thatwas made up of a Cylinder and two spheres, I wanted to chop off the front edge, and on a whim I decided to use the "clipped_by / bounded_by" method discussed in the manual.

Rather than just shearing the front of the object as I expected it cut the object open, exposing the interior of the shape.

The more normal method of using a "difference" does not expose the inside.

This might be worth experimenting with!

Aspect Ratio

A Little known ( or at least little used ) feature of the camera is the Aspect ratio. I've used this in the past when I've rendered a non-standard size image. If you make and extra wide image you have to widen the aspect ratio or the image gets deformed.

Anyway, last night I actually used the aspect ratio to create an effect rather than avoid one.

I placed the camera close to the nose of a sheep. By playing with the aspect ratio I was able to get one of these "HUGE NOSE" shots you sometimes see on TV. There are other ways to get the same effect by changing the camera type for instance. However as POV-Ray is an ongoing learning experience every idea is a new arrow for your bow.

To change the aspet ratio, include the "up" and "right" settings in your camera block.

up <0,1,0> right <1,0,0>

Clouds Macro

I'm currently working on a macro to produce clouds. It s not finished yet so I cant post anything but you might find the principal interesting.

Currently I pass the macro a Size,Count, Samples,Seed and Flat-Bottom parameters.

Size is the length of the side of a box in which the could will appear ( the macro returns a box with a cloud in it).

Count is used to produce a blob made with a number of spheres equal to the count. This Blob is then used in an object pattern media statement in the box.

Samples is the number of samples used by the media.

Seed is the random seed value used by macro to place blob elements.

Flat-Bottom if true, is used used to move most of the blob spheres in the bottom third of the box, upwards, in effect flattening the bottom of the cloud.

Overall its going quite well. But sadly as media takes so long to render the macro is going to take a lot of effort to perfect. I will post it when finished.