How you can help us to make Blender better

Hi,

We just released Blender 2.67b yesterday, the second bugfix release for the Blender 2.67 version. In a 2 month release cycle this is not really nice, and we all would like a stable Blender release. I don’t blame anyone, errors happen and they can happen everywhere. But I think that together, we can do better. :) So the question is how we can avoid those “a” and “b” update releases.

We always release an release candidate, about 1 week before the real release happens, which gives everyone time to test the new version.

Here are 3 questions you should ask yourselves:

  • Do you download the release candidate (RC)?
  • Do you test the RC with your everyday blend files, to see if the things you usually do, still work?
  • If you find a bug, do you report it to the bug tracker, so we know about it?

If you can answer all those 3 questions with yes, it’s great and I want to thank you for that. If the answer is no though, I hope that you will reconsider! Please keep reading.

How you can help us to make Blender better

Before each release, we Blender deveopers run some tests (which we call a regression suite), to test areas of Blender. If you are interested, those blend files are inside our SVN here. The problem with those is, that not all of them are up to date and they cannot cover every possible case. We will try to improve them, and keep them updated, and hopefully this will help a bit.

The most important thing is user testing though. You have a lot of blend files, and you use Blender in all kinds of areas. This is really important! Only you can really test a wide range of scenarios, and check your actual production files.

A few people were worried about the small time-frame, between the rc and the final release, but I don’t see this as a real issue.
We get reports about critical bugs, a few days after the official release already, so it should be possible to find the bugs soon after the rc has been released as well.

I know, that the media coverage for final releases is much bugger, but rc’s are announced on blender.org, blenderartists, blendernation and facebook and co, and that should reach out to a lof of people, at least those who are more involved in the community anyway.

It is of course fun, to download an rc and only test new fancy features, but bugs in new features are not as critical, as bugs in existing tools. Also, I have seen quite some people posting errors, but not in our bug tracker, but in a webforum or so. We cannot check all different kinds of webforums, so we rely on you posting bugs into our bug tracker.

If you want to help us and make Blender better, this is how you can do it:

  • Download the release candidate, spread the news with other blenderheads.
  • Have some fun and test new features, read the release log to check what is new.
  • Open your everyday blend files with the rc, files you usually use, and test them. Can you still model the object you did with the last release? Is rendering still working? …
  • If you find any issue or problem, either in an existing file or a new scene, report it, it can be a bug! If you are unsure whether it’s a real problem, read the release logs again, to see if something changed in the particular area of Blender, maybe it’s just a wrong setting. If this does not help and you still have the issue, or you are still unsure, report the bug!
  • Please report bugs to our bug tracker, only to the bug tracker. Having them in a forum or facebook doesn’t help.

This is of course not a magical solution, but it helps to give you a better and more stable Blender release, and it will make our lives easier as well.

Thanks everyone for reading this, and please consider to help us, if you’re not doing that already. :)

 

Smart Sampling in Cycles

Hi everyone,

some of you may already tried the “Non Progressive” integrator, which has been added in Blender 2.64. The integrator received some fixes recently which brought it up to speed.  Note: You need a SVN build (53719 or newer).

Non Progressive integrator interface

1) What is the Non Progressive integrator?

The Non Progressive integrator is one of the two rendering integrators inside of Cycles. The integrator is the rendering algorithm used to compute the lighting.

The other integrator is the “Progressive” one , which is also the default. You can switch between the two inside of the “Sampling” panel in Cycles.

The Non Progressive integrator also only works on the CPU.

2) What is so special about the Non Progressive integrator?

The Non Progressive integrator gives you much better control over the sampling and the resulting quality of your scene. You have only one setting inside of the Progressive integrator, which is the amount of samples. The Non Progressive integrator on the other hand distinguishes between the amount of Anti Aliasing (AA) samples and Diffuse / Glossy / Transmission / Ambient Occlusion and Light Samples.

“At the first hit it can do multiple light bounces and will take all lights into account for shading instead of just one. This makes each sample slower, but will reduce noise especially in scenes dominated by direct or one bounce lighting. To get the same number of diffuse samples as in the progressive integrator, note that e.g. 250 progressive samples = 10 AA samples x 25 diffuse samples.” (from the Wiki)

3) Where are the pictures?

I did some comparisons which I’d like to share with you here. Click on the links to see the images.

This is a very simple example, yet it already shows the potential of the Non Progressive integrator. Take a close look at the shadow on the ground plane and the glossy/glass cube on the right side. You can download this simple blend file here.

A good comparison of Transmission/Glossy Rays. See the bottom of the sphere, a lot less noise in the Non Progressive Integrator. Also the reflections of the emission planes on the sphere are better anti-aliased and cleaner.

Mike Pans’ bmw scene, in a slightly modified version (No Caustics.) The car windscreen is much cleaner, also the shadow behind the wheels. The noise at the front light is a bit worse though, but this could be fixed with more transmission samples probably.

This is a great example if you render images which have a background image or hdr map. Compare the render times here. Cut by half! The reason for that is the amount of sampling which is done for the background. Usually background images are noise free in  3-4 Samples, so not need to sample that further. The progressive integrator samples the background with 100 samples in that example, which is time consuming. The Non Progressive integrator on the other hand only renders the 8 AA samples and is done really quickly.

In this train station scene (by Florian Schäfer, thanks!) you can notice the much better noise ratio in the Non Progressive rendering.

4) How to setup your scene

Trying out the Non Progressive integrator is easy, but takes a bit of thinking and testing. Again, make sure to use a new build which includes all recent improvements.

Take a scene of yours (maybe start with a simple example like a few cubes) and render the scene once with the Progressive integrator. Let’s say, we render 20 samples. That’s quick and gives you an idea about the sampling. Then switch to Non Progressive, by disabling the “Progressive” check box inside the Sampling panel. Let’s start with a few AA samples, 4 should do in the beginning. Now keep in mind that the AA samples are multiplied with the Diffuse / Glossy etc. samples. Our Progressive render had 20 samples, so let’s try to mimic that.

If you have a lot of diffuse materials in the scene, set the Diffuse Samples to 5. 4 AA Samples * 5 Diffuse Samples = 20 Samples for diffuse materials. If you have some Glossy materials, also increase the Glossy samples and so on. Tweak the settings until you get the same or shorter render time as with the Progressive integrator but a better quality / noise ratio. That’s it.

Now you can increase the AA samples or the Diffuse / Glossy… samples even further to get a nice, clean and final image. Increasing the Diffuse / Glossy etc. samples is faster than increasing the AA samples, but AA samples are also very important. In complex scenes you might need 32 or more AA samples in order to get a good result.

Happy sampling! :)