IRender nXt - Version: ME17

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Permalink Reply by Rich Hart on August 8, 2013 at 7:53am

Can you send me one of your models?

I can render it with the latest version and an older version, like the LJ17 that you were running, and see if I can figure out why things are taking so much longer now.

You can go to this page:

http://www.renderplus.com/htm/uploads.htm

and follow the instructions, to send us the file.

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Permalink Reply by Rich Hart on August 8, 2013 at 10:48am

Thanks, I received your model and am rendering it now to compare the results of the old and new versions.

If you need to download and install the earlier version that you were running when you authorized IRender nXt, you can download the LJ17 version at this link:

http://www.mediafire.com/download/k3qs78tq7s9gigv/IRender_4_LJ17nxt...

You can reinstall it over the newer version.

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Permalink Reply by Drew Mittig on August 8, 2013 at 10:51am

Thanks Rich I appreciate it. 

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Permalink Reply by Rich Hart on August 8, 2013 at 4:43pm

It turns out that the problem that you're running into is a result of a fix we put in for a different reason.

Because there are so many "Lights" in this model created by making a material a light, it is taking a very long time for the rendering to get started in the new version.

I'll try to explain this:

There are 2 kinds of lights that you can add to a model for the renderer.

• 1. Lights placed from the Components dialog such as Spot lights, and Point lights, and lights that are made by setting the Object Properties of a single object. I'll call these "lamps". When you add or create one of these lamps, you add 1 light source  to the rendering.
• 2. Lights that are created by setting Glow on a material. I'll call these "Glow Lights". Each mesh in the model painted with that material adds 1 or more light sources to the rendering, sometimes many individual light sources.

This model has 122 lamps in the model and another 2502 Glow Lights.

If I look at the Statistics dialog in the rendering window I see:

Geometry:
Meshes: 216407
Faces: 1234634
Materials: 166
Lights: 122
Glow Lights: 2502
ArPlants: 0
RPCs: 0

We tell the renderer how many lights to add in each initial pass, since if we add all the lights in the first pass it takes forever to see that first pass. We used to just divide the number of "lamps" by a factor that you set, "3" in this case, and add that many lights each pass. We were not accounting for the Glow Lights in this calculation, so it used to take many more passes for all the lights to start to work.

So we fixed that by now using the total number of all the lights to calculate he number to add in each pass.

If you I look in the Statistics for rendering for the LJ17 version, I see that we were adding 41 lights per pass. So although you started seeing the results more quickly, it might take over 60 passes before all the 2624 of your lights would start to light up.

In the latest version, we now add 866 lights per pass, which is just killing that first pass.

One answer to this is to use materials as lights as little as possible.  Sometimes they work fine, like a sphere with a glow added to it's material only adds one light to the renderer, while a surface, depending on the way the faces are connected to each other, may add hundreds of individual lights.

We wrote the Light Query dialog for exactly this purpose, to help us find where the lights were when we had a model with a lot of lights. The numbers shown on it don't perfectly correspond with the number of lights that end up in the rendering, but it can give us an idea of what's going on.

If I use the Light Query dialog on your model, I see that one surface with a glow material on it that may be creating 537 lights. 

We will see if we can speed things up by combining all meshes with the same Glow Material to be a single light in the render. We'll need to see how that works. We'll also discuss how we can better warn you about models like this, and/or add more functions to identify multiple light sources. 

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