Render View Question ...
 

i've noticed that when you apply a displacement map to an object the render view cropping changes, as if zooming in, as you increase the alpha gain when rendering. The camera position and settings were not changed so why does the render view change. Taking the alpha down to zero renders true to the views camera settings and position. But as I increase the alpha gain settings, to produce more relief, the render view produces a more cropped in view. As if zooming in on the object. Why.

if I understand right, I don't think you're seeing it zoom in, but rather, you're seeing the object being displaced outward, increasing it in size, making it larger in your view. If you need it smaller and can't adjust the displacement's intensity, I suppose you'd need to make your original object smaller. Or zoom your camera out.

Thats interesting. I guess it makes sense too. If the displacement is doing what its suppose to than the physical dimensions of the object would be increasing, and thus the zoomed in look. It seemed so radical though with just a slight alpha change. I didn't consider the geometry change would produce such a change in the render view. Thanks Mike ... its almost too obvious but that must be it.

Hi Mike ... This is the image I'm doing the displacement on. I'm experimenting with actual geometry changes to the tread, as an alternative to bump mapping or using the math data. It a test of render time. Keeping the entire background in crop is important to client.

Just read the guidelines on image size and cropping. This is way too large. I wasn't paying attention. This will not happen again. I understand server overload and will be more sensitive to that down the road.