Acrionx CG Arts and Animations

Home | Tutorials | Freebies | Gallery | Links | Contact | Register | Login

LuxRender Tutorial: How to Use LuxMerger to Merge Rendered Scenes

I noticed there is a luxmerger.exe executable file in the LuxRender directory. I have never bothered to find out how to use it. Eventually, however, I find myself with a reason to want to merge renders. What it does is merge FLM files which are files that LuxRender periodically saves to after a certain amount of light samples were gathered. In order for LuxMerger to work, all of the settings in the scene for each FLM file must be identical.

Why Use Luxmerger?

One reason you would use LuxMerger is if you have several lights in a scene. I read on that you can render your scene faster if you render it one light on at a time and then merge your renders together.

I found an additional reason to use LuxMerger. Below are images of a partially rendered scene. I did not like the woman's outfit material in each of them and I kept going back and made changes and start the rendering all over again. I was trying to go for a leather material look.

This one is not shiny enough and not dark enough.

First render

This one is shiny but way too rough.

Second render

This one looks more like latex than leather, not what I was aiming for.

Third render

This one just looks just plain weird.

Fourth render

It took some trial and error and a lot of time but I finally got the material to look like leather.

Fifth render

Some of the renders above have been rendering for only a new minutes but others have been rendering for over several hours before I can see how well the material actually looks on her. You can tell how long it has been rendering by how grainy the picture is. The longer it has been rendering, the less grainy it is.

I should have tested out the material first by applying it to an object and exporting the scene with only that one object and render it in LuxRender to see how it looks. When you have only one object within a scene, the scene renders fairly quickly. You can see how the material looks within a minute or less. So that's one lesson learned. The next lesson is how to use LuxMerger!

How to Use LuxMerger

So now I have these FLM files saved from all the previous renders, which really sucks -- all that time and electricity wasted. But fear not! They don't have to go to waste! We can use LuxMerger!! So instead of deleting them, I will merge them into the FLM file of the last render that I did like to increase the samples per pixel of the final render! So here is how you do it on a Windows computer:

1. Move your FLM files into the LuxRender directory that contains the luxmerger.exe executable file.

Move FLM files to LuxRender directory

2. Now open up a command prompt window by going to Start --> Run and type "cmd"

3. Now type "cd" and the path to directory that contains your FLM files. In my case, I type:
cd C:\Documents and Settings\
All Users\Documents\LuxRender\LuxRender_32_SSE2_NoOpenCL
This takes you to the directory containing the FLM files.

4. Now you can issue the command to luxmerger.exe to merge the FLM files. As you can see from the screenshot above, in my directory, I have the following FLM files:


I want to merge them into a new FLM file called merged.flm. So here is what I type:
luxmerger [-o merged.flm] one.flm two.flm three.flm four.flm five.flm
You will then see LuxMerger merging the files.

Using luxmerger.exe on the command line interface

5. After several minutes, you will find the merged.flm file appear in the same directory as the other FLM files. You can now open up LuxRender and choose File-->Load FLM and select the merged FLM file to open. And here is the image form the merged FLM file.

Final result

You can tell from her outfit, the outfit material is made from all the previous renders blended together, most noticabe is the second render which had much more samples per pixels.

Well, that wraps up the tutorial. If you find this tutorial helpful to you, please show me some love by making a donation.

Terms of Service | Privacy Policy

Copyright © 2012 All Rights Reserved