Reflections on a new sketchup exporter for LuxRender ?

jenujacob · 19 Jan 2009, 07:16

Here's a list of differences between sketchup pro and the free verion!
ciao!

radiance29 · 19 Jan 2009, 08:50

Hi,

Thanks for your replies, i'm keen to hear more opinions/feedback

Radiance

Gaieus · 19 Jan 2009, 09:27

Hi Terrence and welcome!

As JJ says (although he's a Kerky addict), there's always room for new things and a user never knows when he might want to use this tool or that tool for a particular job.

As far as ruby plugins go, there shouldn't be any difference betwen the Pro and Free verions of SU (me saying this being a non-scripter either).

In any case, I don't want to move this topic into the Ruby Discussion forum now but please, make a (maybe more "specific") post there as well and hopefully some of the guys writing exporters (like Whaat for Indigo or Tomasz for Kerkythea) can halp you with the baics.

remus · 19 Jan 2009, 09:48

I agree with kwist, contacting whaat would be a good starting point. You could also download su2kt form here: http://www.crai.archi.fr/RubyLibraryDepot/Ruby/em_fil_page.htm to get an idea of some working exporter code.

edit: sorry kwist, i wrote that then investigated a bit further and found you were right, so edited my post.

Stinkie · 19 Jan 2009, 09:52

Hi Terrence. There's some great images on your site. LuxRender looks quite interesting.

As for the SU exporter, here's my two cents.

I am not a photographer

Really, I am not. If I wanted to wonder about aperture, shift lens, and what not, I'd toss my Mac, and get a camera. What does this mean in terms of the exporter? This: the possibility to generate a depth map should be included, and SU's parallel projection and orthographic views should be supported. In a WYSIWYG manner, I mean. Set the view in SU, done.

I am not a physicist

Ah, materials. Where would we be without them? For a render to look good, you need decent materials. I know this. Therefore I have no problem with spending some time at setting them up. Howeverrrr ... I do NOT want to write code, nor do I want to plough trough cryptic prose on such concepts as 'nd', 'transmittance', and what not. This is something Whaat has understood well. He's provided a whole bunch of material presets with SkIndigo, which can be applied to your mats. Further tweaking can be done using two sliders, which set reflectance and roughness. This, in my opinion, is the way to go. Doesn't matter if one cannot obtain 100% physical correctness that way. A mat that looks good, is a good mat.

I am not a Max user

I use SU. Nice app, but it's got it's limitations. Lots of geometry and big texture maps will drag SU down to a crawl. Thus component support and externally referenced textures are a must.

That's it. For now. Good luck with your app.

kwistenbiebel · 19 Jan 2009, 09:52

@remus said:

kwist, lux is unbiased a la maxwell, indigo etc. so you wont get speeds similar to vray.

I know that Lux render is an unbiased engine Remus.
But Radiance is also talking about Photon Mapping and Raytracing methods, which are calculations that are mostly used in biased engines a la Vray.

Gaieus · 19 Jan 2009, 09:55

@unknownuser said:

Lots of geometry and big texture maps will drag SU down to a crawl. Thus component support and externally referenced textures are a must.

Not only externally referenced images and components but proxy components and instancing would be nice, too.

Stinkie · 19 Jan 2009, 09:59

Ah, yes. Those too.

radiance29 · 19 Jan 2009, 10:18

Hi guys,

Thanks for all your replies.
I will take them into account and have already sent a PM to whaat to ask for his contact details/questions.

Regarding biased/unbiased,
I see a lot of people placing a label on a render engine of either 'unbiased' or 'biased', and the first label a renderer receives will generally mean the public will always perceive it like that.

Lux supports various algorithms, including biased and unbiased ones, so the choice of easy of use / speed / quality is up to the user.

Greetz,
Radiance

Gaieus · 19 Jan 2009, 10:23

@radiance29 said:

...Lux supports various algorithms, including biased and unbiased ones, so the choice of easy of use / speed / quality is up to the user...

Just like Kerkythea.

kwistenbiebel · 19 Jan 2009, 10:56

Hi Terrence,

Imho, The best way to go is contacting Whaat.
He developed the (Sk)Indigo plugin and other great plugins.
By now he must understand all the pitfalls when coding a Render engine for Sketchup.

I don't think whaat will be willing to write yet another free exporter, but maybe he is willing to give some advice.

As a user of different render engines for Sketchup, I can say there is room for another (free) render engine.
The things we currently miss in the unbiased range of engines, is a way to seperate the sun from the skylight, for instance for overcast days.

Also, rendering out 'channels' for compositing is something we miss: reflection channel, matte channel, shadows channel etc...

I am very interested in what exactly the photon mapping and raytracing component in Luxrender produces.
Vray like? Hybrid?
Currently there is no real good Vray clone in the open source/freeware section, at least not one that produces the same quality.

tbd · 19 Jan 2009, 12:12

Is there any C/C++ API existing or in the works which would allow more direct control of sketchup's API ?

http://code.google.com/apis/sketchup/docs/downloadsdksubmit.html

it would be nice to have a generic exporter and be able to add different render engines output formats (Podium, VRay, Kerkythea, Indigo, ...) - this way everyone will benefit - the users will be able to test different render engines with no or minor tweaking and us, the developers, can concentrate on other things (and not reinventing the wheel, againi and again).

Frederik · 20 Jan 2009, 08:58

@kwistenbiebel said:

The things we currently miss in the unbiased range of engines, is a way to seperate the sun from the skylight, for instance for overcast days.

Not sure I understand what you mean, Chris...
Wouldn't this be taken care of if you're using a HDRI...???

@kwistenbiebel said:

Currently there is no real good Vray clone in the open source/freeware section, at least not one that produces the same quality.

Can you please elaborate on this a bit further...

kwistenbiebel · 20 Jan 2009, 09:17

Hi Frederick,

The lighting a HDRI produces is flat, meaning the shadows are not pronounced (unless it is IBL enhanced like a texture on a dome or something)
A 'sky/sun separation' would mean that you can control the intensity of the physical sky and direct sun seperately.

In most render engines, sun is either 'on' or 'off' and the intensity is calculated by time of day but not tweakable besides that.
(In other host apps (3DsMax,C4D, etc..) the sun is an object (infinite light) with an intensity that can be set. Sketchup hasn't got that. ).

Fryrender is the only SU based render engine where you can control sun intensity seperately from sky by using layer blending.Physical sky on layer 0, sun on layer 1 for instance. (Kerkythea might too but not from within SU).

toxicvoxel · 20 Jan 2009, 13:32

@unknownuser said:

it would be nice to have a generic exporter and be able to add different render engines output formats (Podium, VRay, Kerkythea, Indigo, ...) - this way everyone will benefit - the users will be able to test different render engines with no or minor tweaking and us, the developers, can concentrate on other things (and not reinventing the wheel, againi and again).

Alternatively we need to develop a spec for a Sketchup xml specification which can be used by any rendering- or indeed any other application to interrogate a Sketchup model in an API-neutral way. This could also be an ideal import format that can be targeted by any modelling application without developers investing a huge amount of time developing an understanding of the different Sketchup API's.

Gaieus · 20 Jan 2009, 14:04

dae (collada) is already supported by many apps and is kind of becoming a generally accepted "standard" (or at least a good candidate). Also, it is in xml format which many (or at least some) exporters such as SU2KT also use.

Frederik · 21 Jan 2009, 05:58

@Kwistenbiebel...
Thanks for your explanation...
Let's see what can be done with future applications...

radiance29 · 21 Jan 2009, 06:08

Hi guys,

Thanks again for all your replies and ideas

I've decided to go ahead with it and start my planning phase.
I'll report on these forums once i have something.

Radiance

radiance29 · 21 Jan 2009, 06:16

Hey,

I forgot to ask, Would it be possible for some people to send me some sketchup scenes which i can use during development/testing of my exporter ?
I've never used sketchup before, so it's not going to be easy to make some advanced scenes straight away...

If you have something you want to send, send me a PM and i'll get you my email adres...

Thanks,
Radiance

l.frisken · 21 Jan 2009, 07:41

just search the google 3d warehouse and you'll find many!

otherwise, i'm sure that there will be people willing to give theirs