White points in KE04

Hello,

What are these white points on the walls around the girl? they seem to come from reflexions.

I already see that in the past on very reflective surfaces (posted few months ago), but I didn't have the problem in the same image in KC23.

A bit after at 170 passes, more and more white points

Below is the rendering with KC23. No white points.

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Permalink Reply by Alain Bonnefoy on June 5, 2011 at 1:38am

One point again; you didn't explain where the difference comes from between KC23 and KE26. I can understand two versions can give a different result as each new version is suppose to improve the rendering but in this case, difference is a bit strange as I don't really understand what these artefacts are supposed to represent.

I suppose it could be explained by a difference in the engine code. bug or really needed addon.

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Permalink Reply by Alain Bonnefoy on June 5, 2011 at 1:54am

So, I tried to render the RPS-2 scene in low and high resolution in packet mode and after almost 200 passes no problem.

Then I tried to render my "vue laterale nuit" scene in the same conditions and from your skp file and after 19 passes, white dots comes around the ceil.

After 26 passes, more dots:

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Permalink Reply by Alain Bonnefoy on June 5, 2011 at 2:05am

I send you the nXt_batch via yousendit.

On the right part, you can see white dots at the 4th passe.

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Permalink Reply by Render Plus on June 5, 2011 at 6:42am

Oops - You I had earlier asked:

Are you using the Path Tracer engine, or the standard Packet Engine?

And you responded:

I was using packet tracer.

But I failed to read the response correctly.

That changes everything, and means we should be using the Glossy and/or No Light Source Reflections mentioned above.

Packet Mode attempts to tun faster by grouping the pixels, light, etc. into "packets" but sometimes that creates artifacts such as you have seen.

One solution is to switch to the Path Tracer, and wait a long, long time. The other is to try some of the settings which have been added to help with this.

I will see if I can get the dots. (This should be much easier when I am using the proper engine), then I will try "No Light Source Reflections", the glossy setting, and/or both.

Alain Bonnefoy said:

Well ok Al

First, it seems you use path tracer engine. I used packet mode as it gives a less granular picture without to wait for a long time so, Can you check if the problem doesn't come from this mode?

Secondly, can you precise which version do you use?

I'm going to reinstall KE26 to render the model you sent to me.

Just a poiint, it seems we still have the problem about librairies not found on Windows 7 64 bits. Expecially when we try to choose an hdri sky.

Regards,

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Permalink Reply by Alain Bonnefoy on June 5, 2011 at 11:06am

Ok Al, but again, where does the rendering difference comes from between KC23 and KE26 because we can ensure now that the result is not the same with the same setting.

Normally packet mode and path tracer are supposed to give both a quite close result (ok maybe path tracer can be more precise ....) and that was the case until KC23, then with latest version, these dots appear so, I wonder if the actual result is really an expected behavior or not.

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Permalink Reply by Alain Bonnefoy on June 5, 2011 at 12:09pm

I think your packet tracer is really really good so don't damage it please. lol

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Permalink Reply by Render Plus on June 5, 2011 at 3:15pm

If I can get an example here which fails, I will be able to make a better response.

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Permalink Reply by Alain Bonnefoy on June 6, 2011 at 12:05am

Didn't you get the problem in packet mode?

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Permalink Reply by Render Plus on June 6, 2011 at 9:31am

Not initially.

I need to try rendering from your Batch Zip file to see if I can duplicate it using that,

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Permalink Reply by Alain Bonnefoy on June 6, 2011 at 11:15pm

Strange anyway because I got it also from the skp file you sent me, just selecting packet mode.

I think also that you don't get white points if you render the zoomed area (RPS-2 I think) but only if you render the whole scene.

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Permalink Reply by Alain Bonnefoy on June 11, 2011 at 9:24am

What about this problem Al please ?

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Permalink Reply by Render Plus on June 11, 2011 at 9:53am

I am sorry this is taking so long. It is difficult for us to solve a problem if we cannot duplicate it.

I would appreciate your help in solving this. If I can every get it to fail with the latest version, then I can see if it worked with previous versions, and get the render developer to help see what might have changed.

I rendered the zipped batch file you sent with the latest version, then I downloaded version KE26.

I am unable to try any of the suggested fixes here unless I can get a model which fails.

They both rendered ok. I am including the image below after 1200 passes with the packet mode

At this point we can move in one or both of two directions:

1. You try using the "glossy material" and/or the "No Light Source Reflections" setting for the girl and back wall and see it that fixes things for you.

If that does not work for you, then I think we need to try to create a new model for testing.

2. For the new model (you could start with the model I sent you, which you said also failed):

a. Use an all new file name (e.g. white_points_problem)

(It is getting confusing having so many files passed back and forth with similar names)

b. Make sure there are no accented characters in the SKP file name.

(I want to make that file names are not causing the problem)

c. Use the latest version of IRender nXt - current KF06

d. render the model, save a JPG from the rendering so I can use it to check the settings.

(When you save a .JPG we save the settings in the image file)

e. Stop the rendering as soon as it starts failing so I will know how many passes I should be testing.

f. Zip up the nXt_Batch file after rendering

g. Save the SketchUp model after rendering.