Indigo Renderer Forum

Hi guys,

This is about lights problem.

I've precisely spotted the cause, but I don't find it logic :

I made some spot lights with chrome collars.

When I use them the light is completely inefficient.
When I delete the chrome collars around the spotlights then they become so bright I got to lower their gain to get a correct image.

So is this due to the fact that chrome stuck to a light source just makes it ultra slow like glass does ? In that case what kind of tip can I use to make my chrome collars around my spot lights ?...

Thanks

EDIT : I've noticed the light was not anymore on the lightsource...which seems turned off but on the interior part of the chrome collar...just as if the collar stole / sucked the blackbody's light.

An image of your model would help...

Hi zeitmeister,

Yes indeed
Here are some photos + more detail :

It's about the 3D model, when I physically smooth the inside edges (marked in dashed red) of the collar around the light it goes crazy.

So when I sharpen them back everything works fine again..I've lost weeks trying to balance those lights in the indigo guy when it was all about modeling...

However if anyone can explain to me why it behaves this I'll be happy to hear him...I mean even if it slows down the computing process, it shouldn't "steal" the light from the source. Also I forgot to say : when I only use erroneous lights in a scene, I got really buggy behavior :

If the gain is less than 25 it's dark.
If the gain is 25+ it's too bright.

Even 24.999 gives a dark result, when 25 is ultra bright as you can see on those shots : You can imagine how crazy I got before I find this critical ladder lol...I played hot and cool during a little while until I find.

Hi Chocochoc,

your problem seems to relate with SkIndigo more than Indigo itself so I'll let the educated people answer you on specific aspects. However I have a question, and one theorical explanation.

In theory, it is possible that the edge rounding plugin is changing the vertices order in a manner wich forces Indigo into reconstructing tapping faces were they should not be, that is, across the aperture. I can't tell for SU, but in other 3d applications one possible fix could be to export the edited chrome ring geometry to a third party format then import it back into SU. But SU users would tell better.

The question is: have you used Indigo mesh subdivisions on top of the SU modeling of the ring ?

The sudden change in intensity I can not explain by Indigo. Did you check into the Indigo UI if the close values were preserved into the exported scene ?

If the intensity test was run against Reinhard tonemapping then that's not intensity that you are controlling, powers discrepancies rather. Linear and Camera tonemapping methods have a fixed (absolute) sensibility to the light while the Reinhard method has a sensibility automatically adjusted to embrace all exposures in the scene, or nearly. It is relative

Hey CTZn,

thanks for your help again,

well, mesh topology certainly has a role in that problem...too bad Sketchup hides this side of modelisation so much.

Easiest way will be to model a similar light in blender and then try the difference, so I'm going for that. In the end I guess it's better as a workflow than modeling the collar in skp then blend it then skp again.

To answer your question, no I didn't use any subdiv other than the round corner for sketchup.

I always avoid reinhard, the result is always pale and I can't balance the light since as you say it automatically adjusts it so everything is medium. This is camera tonemapping using the dscs315_2 camera profile.

Thanks for your intervention, I'll let you know about the result with a blender generated chrome collar !

The sudden change by a threshold is probably a SkIndigo thing. Could it be also that the walls were turned into chrome by mistake ? The results could be similar-ish.

Could you explain, if still relevant:

EDIT : I've noticed the light was not anymore on the lightsource...which seems turned off but on the interior part of the chrome collar...just as if the collar stole / sucked the blackbody's light.

Hey CTZn,

Nop the walls are fine, since I made a lot of 24.99 then 25 then 24.99 then 25 and it stwitched everytime (and also you can see in the sketchup viewport easily which material is applied).

So I guess maybe it's a skindigo story...lol when I think I got so mad at indigo's light management.

Normally you should be able to check the final values used into the Indigo GUI, because at this point I am not sure really what is going on.

Is gain still found into the latest SkIndigo ? You should rather use the emission scale system I presume.

Sorry to bother you, but could you please state the applications versions that you are using ? Host apps, exporters, Indigo. Just to clarify, thanks.

Hoho, I see you are up early !

Well now that I look I'm quite surprised I'm still on indigo 3.0.12 I thought I remembered being on 3.0.14.

Skindigo is 3.0.15
Sketchup 8.0.4811
I use Windows 7 64 bits

I'm gonna test a blender model so we got more info.

My pleasure !

Ok CTZn,

Done it with blender, sent it as an obj with some old exporter that stopped being developed since 2009 and it just worked perfectly.

note this working smooth model I'm talking about is made in blender, not importer from skp then reinjected after a blender trip.

Expectedly, the new geometry should be ok with SkIndigo 3.0.15 and later. Let us know if that's not the case, if you ever tested that.

Nowadays with Indigo, emission scale is the best way to set light intensities (NOT power and efficacy, wich should work as well that said).

Hey CTZn,

Yeah the lumen input ? Since I only manipulated with the buggy model I couldn't try it correctly, I'll give it a try again.

However, in the end I always go in the lightlayers panel during render and tweak the values like crazy to get what I want, especially the gain input :p So I can't promis I'll leave it in peace !

Well It's the skindigo 3.0.15 I'm using and still I got that so...well..anyway today I was trying to import some backed particle system into Sketchup...and how can I say, it's like trying to catch your right ear with your left foot rather than using your available right hand....
So from now on, everything with subdivs and sexy stuff I'll just do it in blender and basta...for the low poly and cubic models (as for the measured tiles textures) I'll continue on skp as much as I can.