Redshift3D Per Trail Color
Rendering X-Particles per trail colors & creating abstract art

2 in 1

Today I am primarily focusing on a feature in X-Particles that has been a large issue in the Redshift3D community. At least for the artists using Cinema4D and X-Particles. With some new found knowledge I hope to shed some light on that issue as well as show you some ways to make some abstract art like the images below.

History

Redshift3D has always been unable to render per trail coloring due to a limitation in the X-Particles SDK. As noted in the Redshift3D documentation (captured 6/30/19).

Due to this limitation, you had to settle for random colors or cheat a little and convert the random colors to grayscale so you could then colorize them yourself. This was a very round about way to get color variation in the trails, but effective if you really needed it.

I will step back a little too, if you are unaware of how the trails can even contain color to begin with. In X-Particles you can designate the particle color through a variety of methods. When adding an xpTrail object to your particles, the particle color is carried over to those trails through the xpTrails object “Trail Color Mode” parameter. By default this is set to use the particle color for the trail color.

Since the xpTrails object creates a spline path from each particle, which visibly gives you the trails that follow the particles, that color data has to be saved to the vertex points of the splines. During the render phase that vertex color data is what defines the color of the trails themselves. Now the color is only used when the trails are swept with polygon geometry. This doesn’t have to be done at the object level thankfully.  It is literally handled by Redshift3D at render time. This optimizes the rendering speed and keeps you from needing a lot of RAM to process actual polygon geometry in the scene viewport.

That vertex data though wasn’t readable by Redshift3D because of the SDK limitation mentioned earlier. Essentially, the data couldn’t be reached by Redhift3D or the user because it was trapped behind a wall.

The Great News

On April 1st, 2019 Kostas Karanikolas of Redshift3D posted a reply to a per trail color thread stating “…I have some good news. The latest X-Particles early access build (690) comes with an updated SDK that allows extracting the color and thickness of XP-Trails. Our next build will include support for this.”.

This was amazing news. I of course did not notice this great news until now (two months later). Regardless, the feature is now available after all this time and works wonderfully. Connecting up the Redshift3D material to properly use the color data was another hurdle though. Thankfully it didn’t take me too long to figure out the process. Super simple too.

Shout Out

I also want to include a couple references that I will be mentioning in the video tutorial just so you have quick access to them. The first being HDRI Haven. Free 1K – 16K HDRI images in this collection can be used to light your 3D scenes. These images are incredible, and really add so much realism to your scenes. Definitely check them all out. You can also support Greg Zaal’s efforts through his patreon page.

Also I would like to point to another video tutorial which may come in handy for you if you want to prevent intersecting trails once you render them. This Greyscalegorilla tutorial about X-Particles avoidance by Chris Schmidt (now answering Cinema4D questions every Wednesday at 2pm CST at Rocket Lasso)

Tutorial