In this tutorial you will learn how to use Retimer to change caches playback and how to optimize caches.
In Maya, select File->Open, and from [MAYA]/FumeFX/Tutorials folder, select the file Tut_06_start.ma.
Retimer allows you to change the playback speed of existing caches while Optimizer helps you to keep cache sizes at the minimum.
In Tutorial 5 you have learned how to use Wavelet Turbulence and we are going to use it in this tutorial as well but we won't go in detail.
Because Wavelet Turbulence and Retimer use their own caches for output, make sure that inside FumeFX Preferences, Auto Synchronize Paths is enabled.
Inside the FumeFX Output rollout, change Output Path so that is valid on your machine. Since we had Auto Synchronize enabled, Wavelet Turbulence and Retimer Output paths will be changed as well.
Select the Simulation Rollout and scroll down to the Extra Detail rollout and change the Mode to Wavelet Turbulence.
IMPORTANT: To be able to successfully retime your caches, there is one step that you must not forget. The Velocity channel has to be exported whenever you are going to use Retimer. Additionally, the Temperature channel also has to be exported if you are using fire in your scene. Without those channels, retiming cannot be performed.
Scroll to the Output rollout and enable Export Temperature. Velocity is automatically exported when you have selected Wavelet Turbulence Extra Detail Mode.
Click on Simulate button and wait until simulation ends.
For this tutorial we're using mental ray as a renderer to create global illumination effects.
Select mental ray for rendering and render frame 50.
Keep image in render view for comparison with Wavelet Sim.
Scroll down to the Wavelet Turbulence rollout and change Fire Strength to 4.0 and Smoke Strength to 4.0.
Change the Sim. Mode to Wavelet and run the simulation again.
This will compute Wavelet caches with spacing of 0.5 (Grid size of 1.0 and a Detail Scale of 2.0 ??? 1.0/2.0 = 0.5).
Select Wavelet from the Cache dropdown list and render frame 50. Notice much more detail compared to the Default cache!
Now, we're going to retime our caches and to add a slow motion effect in the middle of our animation. At the same time, we will optimize the caches by stripping all the data that we don't need anymore.
Open the Post Processing rollout.
Since we're not going to need Velocity, Temperature and Wavelet Turbulence (Texture) information anymore, select Exclude Temperature, Exclude Veloctity, Exclude Texture checkboxes.
There is another option called Minimize Grid that will tighten grid around non-empty voxels as much as possible. This will result in smaller and more compact caches and faster rendering times. Minimize Grid checkbox is enabled by default. Enable the Retime checkbox.
We are going to use Time Scale Factor retiming method, where its value should be animated as follows. At frame 30 add key. Move time slider to frame 60, change value to .01 and set key. At frame 100, set value to 1.0 and se key. What we did is that between frames 30 and 60, Time Scale Factor goes from 1.0 to 0.1 and back again to 1.0. A Factor of 0.1 means that cache will be 10 times slower.
Since we are going to retime the Wavelet cache, make sure that the Wavelet cache is selected as input cache.
Next change the Sim Mode to Post and click Run Post Processing button.
The following dialog will be opened during the retiming process.
Once this process is completed, you can open your caches folder and compare default, wavelet and post processing cache sizes.
The able to view and render Post caches, you need to change input caches to Post.
Render out the entire retimed animation to see results.