export for houdini

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jiversen
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Post by jiversen » Wed Jan 30, 2008 12:18 pm

dougal2 wrote:Triangles are your safest option, but I think some n-gons will also work - be careful with normals and how the polys are modelled in particular.
I've always wondered: what is an "n-gon"? Polygon with more than 3 sides? Or more than 4 sides?

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dougal2
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Post by dougal2 » Wed Jan 30, 2008 12:21 pm

I think it's actually a generic term for a polygon with any number of sides,
http://www.mathwords.com/n/n_gon.htm

I tend to use it to mean 4 or more.

jiversen
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Post by jiversen » Wed Jan 30, 2008 1:02 pm

dougal2 wrote:I think it's actually a generic term for a polygon with any number of sides,
http://www.mathwords.com/n/n_gon.htm

I tend to use it to mean 4 or more.
Ah, so you're not meant to say the "n", you're meant to substitute a number in there. Otherwise its identical to "polygon", I take it.

Thanks for the clarification.

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Kram1032
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Post by Kram1032 » Thu Jan 31, 2008 2:04 am

I'd say, n-gon is above 4 edges.
3 -> tri
4 -> quad
5 -> pent? xD Nah... poly or n-gon.
.
.
.

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psor
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Post by psor » Thu Jan 31, 2008 2:17 am

I guess it depends on the definition. A n-gon is a polygon, no matter what.
We just need to clarify things a bit more to make our communication a bit
easier. So in our case (3D) we talk of n-gons when it comes to faces with
more than 4 vertices. And the most modelers try to avoid them as hell,
like tris too. Of course it always depends on the purpose of the model.

:P :D ;)



take care
psor
"The sleeper must awaken"

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Kram1032
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Post by Kram1032 » Thu Jan 31, 2008 3:15 am

sounds good :)
Yeah, usually, quads are the best solution... for most purposes.
N-gons (as we now finally have defined them) can screw up the whole geometry in some cases... tris smooth out strange, sometimes, but they still kinda can be used :) (And in case of Indigo, they're actually the only things, besides some special primitves, that you can use at all)

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psor
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Post by psor » Thu Jan 31, 2008 3:39 am

Hehe, ... the point with the quads when it comes to modeling is another
story and should not be discussed in this thread. You can find quite a lot
about this issue on cgtalk.


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psor
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jiversen
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Post by jiversen » Tue Mar 11, 2008 4:46 am

Just to let everyone know, I've made quite a bit of progress with the exporter. There are a few significant areas to still develop but the bulk of it has been done.

http://forums.odforce.net/index.php?sho ... entry44463

I'm having hassles where internal_mediums are rendering out just black. I would love for someone to examine some simple IGS file output for me and tell me where I'm going wrong. Is it my normal definition? Or a setting somewhere? Are there any common snafus that I might be missing? I'll post a snippet later tonight if someone volunteers to read it:)

Also, I'd love for someone to with experience on how to map, say, .mi or .rib camera parameters to the Indigo camera. I've gotten part of the way there but my settings aren't quite there yet since I don't quite have a good mapping of the standard Houdini camera to the Indigo camera. (I figure people are more likely to be familiar with Renderman or mental ray than Houdini...)

Cheers,
Jason

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OnoSendai
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Post by OnoSendai » Tue Mar 11, 2008 5:29 am

Hi,
looks like you're making good progress :)

For working with the camera, check out the exporter writer's guide here:

http://www.indigorenderer.com/joomla/fo ... php?t=1106

There are a few requirements for media objects:
* surface must be closed with no holes
* geometric normals must point out
* lights must not intersect the surface of media objects.
* precedences must be set correctly

See the appendices of the Indigo manual for more info.

jiversen
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Post by jiversen » Wed Mar 12, 2008 5:06 am

Hey there,

Thanks for the information!

I didn't get around to doing anything on this last night but I do have a couple more questions:

*/ If there any way to pipe the IGS directly into Indigo? Most renderers I've use can read stdin and so Houdini just writes away and the renderers pick it up. So far it seems that indigo.exe cannot do this and I might have to write a wrapper for indigo - which I'd prefer not to do.

*/ An installation question: what is the best way to install Indigo? It seems that if I attempt to invoke it from another cwd it will fail as it doesn't seem to search for its setup files relative to the binary path. Ideally I'd like to just add the indigo.exe location to the $PATH and thats that (just pipe to indigo.exe) - everything *should work. Can you explain or point me to a good document for this?

Take care,
Jason

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OnoSendai
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Post by OnoSendai » Wed Mar 12, 2008 5:13 am

There's no way to pipe the IGS directly to Indigo (unless you are using the commercial SDK).

The latest version of Indigo should load setup files relative to the .exe.

jiversen
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Post by jiversen » Wed Mar 12, 2008 5:15 am

Thats good news! (the setup bit)

I'll try to work a solution to the piping without writing wrappers.. I'll let you know how it goes.

jiversen
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Post by jiversen » Thu Mar 13, 2008 8:27 am

I got the mediums to work - it turns out my polygon winding needed to be reversed. Thats good news!

I updated to 1.0.7 and found that the "white_balance" camera tag seems to bork the parser now. It seems like I've added it in the manner described in the PDF file but it doesn't like it. (I renamed it from "whitebalance" under "render_settings" to "white_balance" under "camera" - it used to work in the stable release 0.9.7)

And I also think the russian_roulette_live_prob doesn't work either. (Also renamed from 0.9.7)

If I comment these both out things go through.

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OnoSendai
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Post by OnoSendai » Thu Mar 13, 2008 9:43 am

russian_roulette_live_prob isn't used or accepted any more.
Not sure about white_balance, will check later

jiversen
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Post by jiversen » Thu Mar 20, 2008 12:09 pm

OnoSendai wrote:There's no way to pipe the IGS directly to Indigo (unless you are using the commercial SDK).
Hey there,

Do you think that you'll support piping into Indigo some day? Why I ask is that it's pretty convenient if it can do done this way.

On the good side, the setup is almost ready for any early adopters to give it a whirl - just a couple of niggly things left to do (like fix slight oddness with my camera parm translations).

Cheers,
Jason

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