Enscape: A Lumion user's opinion, part 1

Hi, everyone. First, let me introduce my rendering experience: I mainly work creating 3d walkthroughs for clients, but now I'm switching to stock plan creation. Since 1998 I've used ArchiCAD, Artlantis 4.5 (Pre-2000 version), 3dsmax with native scanline, SketchUp, Kerkythea, Twilight, LightUp, and Lumion, and I've also had licenses for Thea, Octane, and Visualizer, but never really used them; only played with them. I've been beta tester for Lumion and Twilight, and UI translator for Twilight and LightUp. At present I only use SketchUp, Lumion and LightUp for producing videos.

How I found out about Enscape

Enscape: La opinión de un usuario de Lumion, parte 1

¡Hola! Antes que nada, un poco sobre mi experiencia en renders: Mi trabajo principal hasta ahora ha sido creación de recorridos virtuales para clientes inmobiliarios, pero ahora estoy dando más énfasis a los planos de stock. Desde 1998 he usado ArchiCAD, Artlantis 4.5 (Versión antes del año 2000), 3dsmax con native scanline, SketchUp, Kerkythea, Twilight, LightUp, y Lumion, y también tengo licencias de Thea, Octane, y Visualizer, pero nunca los he usado mucho; solo he jugado con ellos. He sido beta tester de Lumion y Twilight, y traductor de Twilight y LightUp. Al momento solo uso SketchUp, Lumion y LightUp para producir videos.

Cómo me enteré de Enscape

The video you see above was shared by Pete Stoppel on SketchUcation about a year ago. Pete said that he thought Enscape had better interior lighting than Lumion or Twinmotion. My first impression while watching the video was that it looked like Lumion 1 and that it relied heavily on SSAO and what seemed like Screeen Space Reflections. But yeah, the GI did look better than Lumion. So I had a quick look at Enscape's website. The stock cartoon character and the explanation that Enscape worked with some kind of alien magic brought to Earth by Dr. Photon we really off-putting... Why the need for a fantasy explanation instead of a real one? Where they former Act-3D employees or current employees moonlighting? Also, the pricing reminded me of what had happened with Lumion and Lumen RT... It was low now, but it might go up drastically in the future. As many of you remember, a full-featured Lumion license started out at 799 euros back in 2010, and it's now 3,000 euros with a yearly upgrade cost of 1,000 euros. Lumen RT started out at 199 dollars and now it's over 3,000 dollars. So I thought: Enscape might be cheap now, but it might become expensive in the future once everyone's "hooked" into it. And it would be easier for Enscape to pull this off, since they don't offer permanent licenses, but only SaaS, or subscription-based licensing. So I forgot about Enscape for about a year.

El video arriba fue compartido por Pete Stoppel en SketchUcation hace un año. Pete opinó que Enscape tenía mejor iluminación interior que Lumion o Twinmotion. Mi primera impresión al ver el video es que se veía como Lumion 1 y que dependía mucho de SSAO y (aparentemente) de Screeen Space Reflections. Pero la iluminación global sí se veía mejor que Lumion. Así que eché un vistazo rápido al website de Enscape. La caricatura del Dr. Photon y la afirmación de que él había traído tecnología alienígena de renderizado fueron un poco repelentes para mí... ¿Qué necesidad había de dar una explicación de fantasía en lugar de una real? ¿Acaso eran ex-empleados o empleados actuales de Act-3D? También, el precio me recordó lo que pasó con Lumion y Lumen RT... Era bajo por ahora, pero podría subir drásticamente en el futuro. Como muchos recuerdan, una licencia de Lumion con todas las funciones costaba 799 euros en 2010, y ahora cuesta 3,000 euros, con un costo anual de actualización de 1,000 euros. Lumen RT empezó costando 199 dólares, y ahora cuesta más de 3,000. Así que pensé: Enscape podrá ser barato ahora, pero podría volverse más caro en el futuro, cuando todos estemos enganchados a él. Y será más fácil para Enscape logarlo, pues no ofrecen licencias permanentes, sino solo suscripciones. Así que me olvidé de Enscape por un año.

This is the cringe-worthy explanation of how Enscape works provided on the website. I'm seriously not making this up.

A second look

A few weeks ago, I noticed Justin from The SketchUp Essentials and Jacqueline from That BIM Girl using Enscape a lot, and the quality looked better than what I saw last year. After checking that Pete still recommended Enscape, I decided to download the trial. Here's Jacqueline introducing Enscape for Revit:

So, after installing the trial and creating my first images in minutes, my first reactions were (remember, I've been a Lumion and LightUp user for years):

How did it know that I wanted planar reflections in those places? Or are those screen space reflections? How did it know this is supposed to be water? Is it copying my LightUp settings? Gosh, it's calculating too many reflections at the same time! It's going to crash! Wow, it's respecting the FaceMe setting in plants! Hey, I can set this material to emissive... Wait, what? Emissive materials don't affect performance? But they're suppposed to be computationally expensive! Why do reflections get blurry when I move around? There's something really clever going on here... How can it calculate indirect lighting in real time? Wait, is it caching the indirect lighting as I move? What kind of sorcery is this??!!

One of my first Enscape images, of my "House Plan 1" model. I still had not figured out how to customize materials, but it was already looking reasonably good.

Another quick try with the "Mercado del Río" model. Here I'm basically testing the "keyword" approach to materials. I did crash SketchUp and Enscape when trying to export, tho.

Realtime GPU Path Tracing

I'll take a detour here to provide some background about the technique Enscape uses. I'm an architect, not a CG expert, so if you have any corrections to make, please leave a comment.

Path Tracing is a rendering technique that can give very realistic results when used properly, but it's very time consuming to calculate for a traditional CPU. The first time I used a Path Tacing engine was with Kerkythea and Twilight Render back in 2009. The results were spectacular and easy  to achieve (almost no settings to tweak), but it took a looong time to render. Traditional Path Tracing is a type of "Progressive Render" method, that is, it starts with a very grainy, or noisy, image and it progressively reduces the noise as it keeps shooting rays, thus better averaging the image. On a CPU, it can take several hours to achieve a noise-free image.

Since Path tracing can greatly benefit from parallelization, and GPUs excel at parallel tasks, there have been several attempts at Path tracing on GPUs instead of CPUs. Previous attempts at GPU Raytracing, such as Octane, Thea Presto, Vray RT, have all worked as "Progressive Renderers", just like I described above, with the difference being that they're much faster: Instead of waiting hours for an image to be noise-free, you just had to wait minutes, and you could actually get a pretty good idea of how the final image would look in just a few seconds. This was quite a revolution: This meant you could even move around and make changes in real time, thus allowing you to iterate design options more quickly.

When these companies want to sell you on how fast their GPU raytracers are, they'll normally only show you a video of it working with lots of direct illumination: For example, an exterior scene with sun and sky illumination, or an interior scene with many artificial lights on. The reason for this is that, with these types of renderers, the more direct illumination you have, the quicker the image noise clears up. Ergo, they normally won't show an interior scene illuminated with only indirect sunlight in their demos, because it would take a long time to clear up. Here's an old demo of Brigade using TWO TITAN cards at the same time:

Newer engines include some form of smart noise reduction in order to give you a cleaner image in less time. The video below is Brigade a year later, during a 2015 presentation. They had found a way to kill the noise, but I could not found any info about the kind of and how many GPUs they used for the demo. And they're still only showing scenes with heavy direct lighting:

Enscape 2 is GPU Path Tracing on steroids

Judging by the look of old Enscape videos from 2015, it seems it did rely heavily on SSAO. However, Enscape 2.0, released in 2017, shaked things up: It switched to real-time path tracing, as stated in their blog here. However, if you remember what I said a moment ago, this normally produces a very grainy image during navigation. It took Otoy's Brigade team several years to arrive at a noise-free solution. So, what are the Enscape team doing different?

This is where things get very technical and I'm at risk of making things up, so here's an article found at AMD's GPU Open website written by Enscape's CEO. There are also some slides from a presentation the Enscape team gave at an NVIDIA conference (PDF). Of course I barely understood anything in those two links, but I did understood this:

• In part, they use AMD's Radeon Rays technology, which is open source.
• They're using every trick and shortcut possible, including rasterization techniques like shadow mapping, and thus use path tracing only when necessary.
• They filter the results in a very, very, smart way to get rid of the noise while at the same time avoiding the typical "noise-reduction look".

Just being able to access that information helped me trust the Enscape team a lot more, even if I didn't understood most of it. I keep wondering why they keep the fake Dr. Photon explanation on their website instead of the real one. BTW, here's a quick explanation of AMD's Radeon Rays:

But there's still a lot of work to do

So, we have already established that Enscape is using some very, very smart optimizations in order to achieve a final, noise-free image in a tiny fraction of the time. However, it seems that Enscape is only applying the smart filtering within each frame, and not between frames. The result is that the GI can flicker. That is, the filtering is done in space, but not in the time dimension. In more technical words, there's a lack of Temporal Stability. Funny enough, this problem does not happen when you move around in real time in Enscape. Here's a quick test of a room only illuminated through a tiny slit:

Here's another example of GI flicker. Notice the flicker in the dining table area:

As stated before, this does not happen when you move around in the Enscape window, so it would indeed be possible to get rid of it in rendered videos. The fact that it looks better in real time probably has something to do with the fact that Enscape's main selling point are its VR capabilities. Video production, at the moment, does not seem to be Enscape's highest priority, as reflected in the very primitive tools for video rendering it currently has.

At the moment, both AMD and NVIDIA seem to be working hard in the real time Path Tracing field. The dream of being able to move around in real time in a very realistically rendered environment is getting closer and closer. A few weeks ago, an Unreal Engine demo using Microsoft and NVIDIA technology left us all in awe showing GPU-rendered real time reflections. Of course, this demo must have used a custom built rig with ridiculously expensive GPUs, but it shows where we're headed:

If you only watch one video of the many I've embedded, the one below should be the one. It shows how NVIDIA is using AI to improve noise reduction in real time Path Tracing, not only across space, but also in the time dimension, thus arriving at flicker-free solutions. Hopefully, we'll see something like this in Enscape soon:

Conclusion and how it compares to Lumion

 There's a lot more I can say about Enscape right now, but I'll reserve it for after I've created a full 3-minute house animation, from start to finish, with it. For now, I'll recap with this:

• Enscape is already using very realistic and efficient rendering technology that, until recently, was only considered a curiosity shown in tech demos. This, by itself, is incredibly exciting.
• Enscape's approach to realism is the exact opposite as Lumion's: Lumion starts with a not-so-great looking image and then it stacks a bunch of effects on top of it to make it look better. Enscape starts with a completely realistic solution and then applies a bunch of optimizations and shortcuts so it can work in real time. For the end user, this means it's a lot easier to achieve realism with Enscape than with Lumion, and that it's a true WYSIWYG rendering solution, unlike Lumion, which stopped being WYSIWYG when it started to rely too much on stacked effects.
  
• Unlike Lumion, it does not have a ready-made "world" of infinite ground and a library of vegetation, people, vehicles and furniture: Enscape is purely a renderer: It only shows what you've modeled, while Lumion is more a "world builder".
• Enscape's focus from the start has been VR and still images production, while Lumion's focus has been on video production. Lumion has come a long way in still images production, but Enscape still has very, very, basic video production capabilities. You literally can only render one shot at a time, so if you want to produce a 3-minute video with lots of 8-second shots, you have to spend a lot of time babysitting the rendering process. They still have a lot of work to do in order to make Enscape a viable video-rendering solution for architects in tight deadlines.

That's it for now. I've just purchased a monthly subscription to Enscape, so now I'll get to work on a full interior-exterior video of a house in order to test Enscape in an actual workflow. Questions? Suggestions? Corrections? Please leave a comment!