Among the new capabilities available in LightWave 3D® 2018 are the volumetric primitives. Antti Järvelä of the LightWave™ development team provides us with a detailed introduction to volumetric primitives in this video.
In the LightWave 3D 2018 Content folder there is a Scenes/Volumetrics/Volumes folder with some sample scenes using volumetric primitives. These offer a good place to start in following up on Antti’s tutorial video to learn more about these new features. You can review these simple scenes for example settings for various effects with volumetric primitives.
Nebula.lws seemed like a good candidate for a more colorful image to accompany this blog entry, than was available from within the video. Simply rendering the scene as originally setup, here’s the VPR render:
So: more colorful, yes. If you know something about astronomy, you’ll know that while this has a nice look it isn’t very true to the look of these phenomena. We’re going to skip over most of those issues, however, and just concentrate on quickly making a nice looking image.
First up, let’s get a look at the basic settings for this scene that we intend to work with:
There is of course a lot more under the hood in these scenes that you will want to explore, but for this tutorial we’re going to make just a few simple changes to get to a reasonable deep-sky-like image.
Nebulae appear in starscapes. Let’s widen up the camera field of view, set a wide-field image of stars as the backdrop image in this scene, and then save a scene iteration. For the camera I started with the UHD setting, but widened up to take in more of the extent of the volumetric.
Here are the camera and Effects backdrop panel settings and a look at nebula_mod_001.lws in VPR:
The backdrop is coming in too bright, and somewhat overwhelming the nebula, making for a muddy picture. However, the final image used for the featured image for this blog entry did indeed start with this. The render was then processed several passes in Windows 10 Photo, with modifications to contrast, exposure, color and clarity.
Another approach that can give us more final options for both the original render and any processing we might want to try would be to process the background image so that it isn’t so overwhelming. We can also modify the gradient away from the pink to a red closer to what we would see in a real nebula. Here is the Gradient Panel and a look at the new saved scene iteration with modified starfield image, nebula_mod_002.lws, in VPR:
That’s a little more like the effect of a really bright nebula against a background of stars. Both versions of the scene offer something to work with when processed in Adobe® Photoshop® or another application. Processing of the initial star image to options between the look of the two versions of the starfield images used could also allow for getting a desired look in a quick-and-dirty direct in-camera render. For VFX work, a more usual approach would be to render just the nebula in image layers, and use a compositor to adjust those layers and starfield background and foreground images to the desired look.
Below are the images used, both processed from original images taken in 2014 of the region of the Milky Way called “The Summer Triangle” for the three brightest stars visible. Constellations included are Lyra, Cygnus, and Aquila and there are emission nebula regions visible, especially in the lower left region.
Astronomical notes on this project: The distant objects that you can see through a telescope such as galaxies, star clusters and nebulae are referred to in the astronomy community as Deep Sky Objects (DSOs). There are several types of the DSOs known as nebulae, but among the most common are reflection nebulae and emission nebulae. Reflection nebulae are visible because they reflect the light of nearby stars, and are blue in color for the same reason as our sky is blue – because the materials involved scatter that bandwidth of light much more effectively than any other. Emission nebulae actually glow, but again this is due to the associated stars – embedded stars pouring radiation into the gas and dust around them ionize the gas, which then glows. A lot of emission nebulae are red, because that is the bandwidth emitted by ionized hydrogen, which is the most common material and the easiest to ionize.
The same material is present in either case, but the result differs significantly. It is not unusual at all for the same cloud of gas and dust to have parts show up as reflection nebulae and parts as emission nebulae, but they would not mix in quite the way the color scheme does in either the original Nebula.lws nor in my deliberately simple modifications. If you wanted to create a realistic image you would use different volumetric primitives for the reflection and emission nebulae in the scene. You would also account for stars present within the nebulae and between the nebulae and the point of view.
The Trifid Nebula region (also known as Messier Catalogue object M20) is a good example of a region where both types of nebula are present. Here is an image taken in 2016 with one of the SLOOH.com online telescopes (image not available for use due to SLOOH.com terms of service for members), lightly processed one pass in Windows 10 Photo to adjust contrast and exposure. Note that there are also dark nebulae present, visible by how they block light from the reflection and emission nebulae. Another thing worth observing is that the stars are many different colors.
There are lots of images of starfields and DSOs on the web these days, and you would likely not find it difficult to locate and get permission for use of some images if you would like to experiment further with rendering images for use in space scenes. Several stock photo suppliers also have such images available for purchase.
Some example Google searches:
If you have questions about the images and videos we share in a LightWave 3D 2018 blog entry, just drop your questions into the forum here:
We will answer in the forum and also update the blog entry with the information.
And if you haven’t seen it yet, here’s what’s new: