I use povray to render molecules from co-ordinate files. Unfortunately the
specifics of my problem demand that I write my own parser (rather than use VMD
, rasmol etc.) that parses from my coordinates to a .pov.

My scene is basically nothing more than a large number of spheres(of different
sizes and colors) Povray works great for me for rendering an excellent high
quality final output.

Unfortunately there are parts in my development cycle where I need a faster
render. Low quality acceptable. Are there any options people would recommend?

I dont even need the full ammunition of a raytracer. But something that could
act on  a similar-to-povray file would be ideal. (or something that a povray
...pov file could easily be parsed into)

The idea is to allow users to adjust molecular positions in an editor (vi or
emacs) and have a second window display these changes dynamically. So I need
something fast. I know I can probably code it in OpenGL or something but I was
just checking if there are other easier alternatives?


Any suggestions are, of course, greatly appreciated!

-Rahul

Post a reply to this message

> I use povray to render molecules from co-ordinate files. Unfortunately the
> specifics of my problem demand that I write my own parser (rather than use VMD
> , rasmol etc.) that parses from my coordinates to a .pov.
> 
> My scene is basically nothing more than a large number of spheres(of different
> sizes and colors) Povray works great for me for rendering an excellent high
> quality final output.
> 
> Unfortunately there are parts in my development cycle where I need a faster
> render. Low quality acceptable. Are there any options people would recommend?
> 
> I dont even need the full ammunition of a raytracer. But something that could
> act on  a similar-to-povray file would be ideal. (or something that a povray
> ...pov file could easily be parsed into)
> 
> The idea is to allow users to adjust molecular positions in an editor (vi or
> emacs) and have a second window display these changes dynamically. So I need
> something fast. I know I can probably code it in OpenGL or something but I was
> just checking if there are other easier alternatives?

If you do it in OpenGL, and you want speed, you need to bother with 
drawing only visible spheres, etc. yourself.

Did you try +q2 on POV-Ray?

Post a reply to this message

> If you do it in OpenGL, and you want speed, you need to bother with
> drawing only visible spheres, etc. yourself.

Exactly! That's the part I wanted to avoid. So to put it better: I was
interested if there was any command line tool that did hidden surface removal
etc. but not with the photo-realistic precision of povray (or ray tracers in
general)

I really don't need light-sources, shades, textures etc. in my intermediate
renders. Although I do have them in the final povray raytraced output which
looks great!

> Did you try +q2 on POV-Ray?

My current command line looks something like this.

"povray  +Irpn.pov +W600 +H600 Antialias=true +FP -GA +Oother_file"

I just add a +Q2 at the end? I tried but didn't seem to change much.

-Rahul

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> I just add a +Q2 at the end? I tried but didn't seem to change much.

Disables shadows, for a start.

You could also try +Q0 but then you won't even get lighting (spheres 
will look like flat circles).

Post a reply to this message

Rahul napsal(a):
>> If you do it in OpenGL, and you want speed, you need to bother with
>> drawing only visible spheres, etc. yourself.
> 
> Exactly! That's the part I wanted to avoid. So to put it better: I was
> interested if there was any command line tool that did hidden surface removal
> etc. but not with the photo-realistic precision of povray (or ray tracers in
> general)
> 
> I really don't need light-sources, shades, textures etc. in my intermediate
> renders. Although I do have them in the final povray raytraced output which
> looks great!
> 
>> Did you try +q2 on POV-Ray?
> 
> My current command line looks something like this.
> 
> "povray  +Irpn.pov +W600 +H600 Antialias=true +FP -GA +Oother_file"
> 
> I just add a +Q2 at the end? I tried but didn't seem to change much.
> 
> -Rahul
> 
> 
> 
turn off the antialiasing. You don't need it and it can slow things down 
quite a lot in some cases.

-- 
You know you've been raytracing too long when...
you start thinking up your own "You know you've been raytracing too long 
when..." sigs (I did).
-Johnny D

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> >
> turn off the antialiasing. You don't need it and it can slow things down
> quite a lot in some cases.
>

I tried turning it off. Acceptable quality degradation. But not too much
improvement in render times.

Downgrading till +Q2 causes no discernible quality loss. But no performance gain
either.

Are there any other non-raytraced analogs of povray? Something that has a
primitive scene-definition language but no cpu-hogging raytraced details?

-Rahul

Post a reply to this message

"Rahul" <nomail@nomail> wrote:
> > >
> > turn off the antialiasing. You don't need it and it can slow things down
> > quite a lot in some cases.
> >
>
> I tried turning it off. Acceptable quality degradation. But not too much
> improvement in render times.
>
> Downgrading till +Q2 causes no discernible quality loss. But no performance gain
> either.

hmm, if no AA nor +Q2 change much I imagine there must be a humongous amount of
spheres around...

Probably won't do much either, but you could try halving the resolution as well.
 And grouping the spheres in unions, as a last resource...

> Are there any other non-raytraced analogs of povray? Something that has a
> primitive scene-definition language but no cpu-hogging raytraced details?

I don't think there's anything much faster or memory-efficient for this kind of
problem (huge amounts of spheres) than a raytracer.

Post a reply to this message

nemesis wrote:
> I don't think there's anything much faster or memory-efficient for this kind of
> problem (huge amounts of spheres) than a raytracer.

Scanline rendering could actually be *slower* if the bottleneck is in 
the sheer number of objects.

Ouch.

-- 
William Tracy
afi### [at] gmailcom -- wtr### [at] calpolyedu

    In the land of the blind, the autopilot is king.
     -- Kim Stanley Robinson, _Red Mars_

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"Rahul" <nomail@nomail> wrote in message 
news:web.47dd8b8e72535d7259eba08c0@news.povray.org...
>
>> If you do it in OpenGL, and you want speed, you need to bother with
>> drawing only visible spheres, etc. yourself.
>
> Exactly! That's the part I wanted to avoid. So to put it better: I was
> interested if there was any command line tool that did hidden surface 
> removal
> etc. but not with the photo-realistic precision of povray (or ray tracers 
> in
> general)
>
> I really don't need light-sources, shades, textures etc. in my 
> intermediate
> renders. Although I do have them in the final povray raytraced output 
> which
> looks great!


Might I suggest you post an example POV file to povray.binaries.scene-files 
so we can all have a play and see if we can speed it up.

Where is the most time spent? In the parsing or the rendering? How long does 
the final render take, and how long do you want (would you accept) the 
intermediat renders to take?

My suggestions are:
    1)    Group logical blocks of spheres together in unions or merges to 
improve the bounding box detection
    2)    Don't put the whole texture in every sphere. #declare or #local 
the textures at the top and use texture{T_MyTexture} in each sphere.
    3)    Remove the textures (especially any reflection/refraction) in the 
intermediate renders. Thiscould be done my #declaring simple textures as per 
suggestion 2 or by surrounfing all texture{} blocks with a #if()#end block.
    4)    I would suggest writing your output to an INC file instead of 
rewriting the POV file each time you do a new molecule. That way you can 
preserve any changes in the POV file with only the geometry of the object 
changing.

Rarius

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> My scene is basically nothing more than a large number of spheres(of 
> different
> sizes and colors) Povray works great for me for rendering an excellent 
> high
> quality final output.
>
> Unfortunately there are parts in my development cycle where I need a 
> faster
> render. Low quality acceptable. Are there any options people would 
> recommend?

Write it in OpenGL or DirectX.  A modern machine should be able to draw 
10000 spheres in real-time (ie at least 30fps), with per-pixel specular and 
diffuse lighting.

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