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See discussion in p.general:
I'm laying out a large facility, and trying to view a tiling grid and
some layout lines. I've noticed that when I zoom way out, I lose some
lines, and get tricked into thinking they're not there, which gives the
floor tiling grid an effect that fooled me into thinking I'd messed up
the scaling.
Some of the yellow layout "lines" (and these are HUGE cylinders) also
inexplicably disappear when I zoom out. Rotate view y*90, and the other
lines disappear!
(Skysphere commented out to provide black background for annotations)
It seems to be an ALMOST regular cancellation of the lines...
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> See discussion in p.general:
>
> I'm laying out a large facility, and trying to view a tiling grid
> and some layout lines. I've noticed that when I zoom way out, I
> lose some lines, and get tricked into thinking they're not there,
> which gives the floor tiling grid an effect that fooled me into
> thinking I'd messed up the scaling. Some of the yellow layout "lines"
> (and these are HUGE cylinders) also inexplicably disappear when I
> zoom out. Rotate view y*90, and the other lines disappear!
That's really typical when you don't use antialiasing and the lines
are less than 1 pixel apart for the render size. Use a bigger render
size and high antialiasing (I had to use +w1200 +h900 +a0.0 +r7 to get a
noticeable grid).
--
Jaime
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Bald Eagle <cre### [at] netscape net> wrote:
> Some of the yellow layout "lines" (and these are HUGE cylinders) also
> inexplicably disappear when I zoom out. Rotate view y*90, and the other
> lines disappear!
The lines are disappearing under the effects of aliasing. This commonly affects
lines falling along the four cardinal directions (north, south, east, west). For
2D images such as yours, it's best to set the line thickness according to the
image's width or height. This can be done automatically:
#declare LineThick = 2/image_width;
where "2" is the target thickness, in pixels. To get lines only a pixel in width
to show up, you'll need to slightly translate the line perpendicularly from its
own direction, like so:
cylinder{
-x, x, LineThick
pigment{rgb x+y}
translate y*1/image_height
}
For zooming in/out, it's helpful to design your camera a bit differently and
alter the line thickness equation like so:
#declare CamScale = 2;
#declare LineThick = 2*CamScale/image_width;
camera{
orthographic
right x*2 up y*2
location -z*1e5
look_at z
scale CamScale
}
The lines might still disappear if they are only a pixel thick, so it's best to
use thicknesses greater than 1 pixel.
Hope that helps!
Sam
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