[erjiang]

Wow, the state of the art in 3D rendering has changed dramatically. The state of the art in open source 3D rendering has changed even more dramatically.

Compare these screenshots from 2013 (although I think POV-Ray was looking pretty dated by then) to renders that come out of Blender's Cycle renderer now.

The big change is that everyone has moved to "physically based rendering" that do path-tracing for propagating light through a scene. Old-school raytracing cannot know how light indirectly bounces off a wall, for example, leading to artificial-looking shadows and flat lighting.

Anyways, anyone interested in making neat little 3D scenes like in this GitHub should try out Blender - it's shockingly easy to make realistic renders compared to several years ago.

Edit: Blender's Cycles rendering engine seems to have been included with Blender since 2011. POV-Ray probably represents 2000s-era tech, although I think it can do more than what's demonstrated in this post.

[TylerE]

That's rather unfair to POV-Ray. These are hardly representative of what it's capable of.

Look through the old IRTC archives, for instance: http://ftp.irtc.org/stills/index.html

People were doing stuff like this (http://oz.irtc.org/ftp/pub/stills/1999-04-30/13hystri.jpg) in 1999.

[beering]

Using this very nice POV-Ray render from Wikipedia: https://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Gl...

It features a lot of effects (radiosity, HDR maps, etc.) which are added on top of its basic functionality. There's been a big shift in how rendering is approached, from the old way of adding a pile of special effects onto your original non-realistic renderer, to a newer way of simulating light as it physically works and using that as the foundation of the renderer.

And there's still a lot of in-between as well, but having gone from 3ds Max's scanline renderer to 3ds Max + Mental Ray, to Blender + Cycles, it feels very different to use.

There are still some effects that Mental Ray (and it looks like POV-Ray) can do that Cycles can't. Photon-mapped caustics seems to be one, although I think LuxRender is FOSS and can do that.

[TylerE]

> It features a lot of effects (radiosity, HDR maps, etc.) which are added on top of its basic functionality

Huh? POV-Ray has supported radiosity for literally decades, since sometime around 1995.

[anthk]

Yep, I'm tired of these kids saying PovRay coudn't do shit as if PovRay had in 1997 the same capabilities of an Irix machine from 1987. They couldn't even be more wrong with that.

I remember seeing photoreallistic images made with PovRay in 1997 you coudn't even do with a GPU today in real time.

Kids today have a lot of ignorance on the 90's technologies, guess why they confuse the 80's and the 90's a lot thanks to that shitty vaporwave culture, having fake nostalgia on something they never truly experienced.

Man, I was playing 720p video under a Divx code in early 00's with a Pentium3 and multimedia was on its heayday, thus, people showing up a CGA pallete has no sense, it already was retro back in the day, you had those in the old MSDOS games you were running under W98 or DOSEmu under Linux, among the rest of the emulators for the ZX Spectrum and MSX for example.

Sorry for my rant, but I had to say it. The late 90's had nothing to do with early 90's, the technology shift we've seen it was outstanding. From DOS under a 286 in my early Elementary school, to W98 emulating Pokémon in my pre-HS days among recording TV streams in a computer, all of that in 5-6 years.

From 30Mhz and 5 1/4 floppies to ~450/600 MHZ a bunch of GB in 1999. For sure PovRay could do a lot more than these kids think.

[cambalache]

The explosion of JS and web development created a culture of people totally ignorant of the hard-learned lessons since the 1960s. That is why you see constant reinventions of the wheel, a shitty wheel at that.

[anthk]

No, I didn't mean that. I mean people today looks like disabled on looking up reliable sources and just parrot a simple opinion on software over 20 years old without looking the Hall Of Fame on its homepage.

That and their selfish issue being unable to acknowledge the 90's legacy and we could achieve in early 00's. For example their previous comment stating as if everything was invented in late 00's/early 10's and we were badly surviving with DOS and Amigas in late 90's, when, FFS, people began to emulate Amigas in '99 with UAE.

Man, we have Voodoo's and Geforce's exploded in late 90's, raytracing was done in software but we didn't do the crippled examples people is trying to show off to the rest as if it was what we truly do in the 90's. Not even close. Even a 286 could do these under half and hour or a full one, but that was the 3D lore from several years ago.

[morsch]

> From 30Mhz and 5 1/4 floppies to ~450/600 MHZ a bunch of GB in 1999.

From rare instances of people accessing their local BBS at 9600 Baud to accessing a worldwide communications network as a matter of course, often at broadband speed.

The past 20 years really have been rather dull in comparison.

[holoduke]

When you are inside a time or period not a lot of change is felt, but once you look back you can see incredible changes. You mention that last 20 years are dull. I think that the last 10 years are the era of smart phone revolution. A pretty big thing. Certainly belongs in the top 50 most impactful inventions and adoptations in human history. In 200 years from now the late 00s will be seen as the start of global connectivity.

[anthk]

ISDN was a good boost over a 56k modem too. Not DSL speeds, but bearable. With Opera and its proxy (and its awesome cacheing options) you had a pretty smooth browsing, almost a clone of DSL speed and usability standards.

[holoduke]

You are right, but the same can be said between 85 and 95. The evolution of realtime 3d graphics was insane. From some low FPS 3d line engines to full blown textured 3d engines.

[anthk]

90-96 is big enough. From the NES/Genesis/286 to the Pentium MMX and the multimedia PC playing MPEG videos and games like Quake. In some PC's you could even emulate the Genesis under DOS, and a year later, the NeoGeo fully, which was "the big thing" in the early 90's. A huge step in six years.

[thdrdt]

Cycles (path tracers) do render caustics but because rays are traced from the camera to light sources the probability that caustics are rendered is very low. This results in noise and fire flies (thats why the glossy filter is set to high in Cycles).

The solution is bi-directional path tracing but this is very hard to implement in Cycles because of the way it is built (according to the developers).

[nunodonato]

ahh good ol' IRTC.

I remember looking at this entry in particular: http://www.irtc.org/ftp/pub/stills/2006-06-30/hideaway.jpg and thinking "how the hell is that possible?"

[minxomat]

That's like saying Flatland (the movie) was representative of the animation tech at the time.

Remember that The Third and The Seventh was done by a single person in 2009, and is entirely modeled and rendered with tech available back then: https://vimeo.com/7809605

[anthk]

http://hof.povray.org/mouille.html

Year 2000. You don't know a lot, and I guess you didn't have a look on the PovRay's hall of fame.

[mcphage]

I love Gilles Tran’s work. I haven’t seen anything he’s created in years, I wonder what he’s done since the Book of Beginnings (http://www.oyonale.com/3D.php?lang=en&section=ldc)

[selfsimilar]

I agree the quality of the render engine is much better with physical rendering, but I still love constructive solid geometry and the ideal of pure curves to define the scene geometry. All these meshes with their triangles! Whatever happened to using NURBS or metaballs or other non-polygonal modeling?

[BubRoss]

Polygons can be smoother and subdivided efficiently at render time without artifacts, which is how they are used now. Nurbs and other curved surface representations end up with huge problems pragmatically when it comes to tools, workflow, visualization, texture coordinates, keeping the surfaces together etc. The list is long. Polygons are very simple in all these areas and can be made smooth at render time so you get the best of both worlds. If you were in a production situation it wouldn't be long before you gave up these ideals.

[Aardwolf]

Every time I see a pipe, bucket, goblet or round thing in a game with otherwise very realistic rendering, I'm reminded I'm just playing a rendered game, due to seeing polygonal shapes rather than a true round bucket/goblet/pipe, and wonder if a quadratic surface would not look better and be more efficient.

Well, that and banding in the gradient of a sky. Those two things break the otherwise so realistic rendering quite commonly.

[klodolph]

I think you may have missed what the parent comment was saying—that the polygons can be made smooth before render time. This is not a question of just faking it with normals. Instead, you can actually just work with a polygonal mesh and then post-process it to make it actually smooth. The classic technique for this is Catmull-Clark subdivision. If you think polygons on screen are offensive, you can just run the algorithm until the individual polygons are under the size of a pixel.

The fact that you see polygons on an otherwise circular object in a game just means that the game isn’t giving you a more detailed mesh when objects are close to the screen. There are a lot of reasons for this, and it’s important to consider that you often get the best overall quality in modern real-time graphics with retopologized meshes. It’s easy enough to make these with a given quality and make lower-LODs from them, but just as a matter of consequence you won’t see higher-LODs than the retopologized version. And why bother making super-high-LOD models anyway? If you look closely at an object there’s a finite amount of texture/model/etc. detail that the game can present. Might as well make the LOD for the model complement the amount of detail in the texture.

The whole process is rather complicated these days, with different workflows (even different programs) for organic objects (like people, animals, demons, whatever) and hard surfaces like goblets, stone tiles, architecture, etc. The two main things people want to do when modeling are sculpt and create a sensible topology, and surfaces like NURBs (or worse, Bézier curves) turned out to be a bit cumbersome for both sculpting and creating meshes.

[tlb]

Yes, but then any edges that should have been sharp get rounded too.

[michal_f]

You can have sharp edges and vertices with subdiv surfaces.

[holoduke]

You can apply the algorithm on a subset of vertices. Exclude all the sharp edges. An extra falloff algorithm can make it even better

[TylerE]

That’s the beauty of CSG though... it’s volumetric, not surface based

[CyberDildonics]

How would that make it easier to work with?

[TylerE]

You can do things like take shape A and then subtract shape B from it and all works, no matter how complex the intersection.

[CyberDildonics]

That is what it is, but how does it make any of the other parts of 3D easier? How would deforming it be easier than surface geometry for instance?

[BubRoss]

I'm not sure what you are trying to say here, constructive solid geometry does not solve any of the problems I mentioned and would have to be treated specially to be raytraced (while being likely being much slower).

Converting it to polygons at a modeling or effects stage is workable but rendering it directly is unlikely to be widely valuable any more.

[TylerE]

There is no need to "subdivide" because the exact volume of the object can be calculated exactly to any arbitrary detail.

[BubRoss]

And what do you subdivide it to? How do you trace rays against it? How do you map textures on to it? How do you visualize it in real time? How do you work with it in a different program?

[selfsimilar]

Pragmatically, I think the real issue is editor tooling. Polygons are much simpler to subdivide and edit and are perfect for real-time interaction, at least much better for high-complexity scenes. At render time, though, you need to use a bunch of extra tricks to get the right smoothing - bump/texture mapping, increased subdivision, etc. But some of these other models might actually decrease the scene complexity and increase quality if you could convert the model at render-time.

[BubRoss]

It isn't just tooling.

> At render time, though, you need to use a bunch of extra tricks to get the right smoothing

Nurbs or any smooth geometry needs to be subdivided too. You can set levels, max size of polygons, smoothness constraints subdivide based on the pixel size from the camera projection or any combination. In practice this is not a problem for polygons or nurbs.

> - bump/texture mapping,

This is orthogonal to the geometry type, with the exception that UV coordinates are far easier to deal with with polygons.

> increased subdivision,

There isn't any increased subdivision, both geometry types need to subdivided. Blue Sky's renderer raytraced nurbs directly but this isn't generally as good as just tracing subdivided polygons.

Polygonal geometry, even subdivided, is typically not a big part of memory or time in rendering in all but the most pathological cases. 4k would still mean that one polygon per pixel would be 8 million polygons, which is going to pale in comparison to texture data typically.

[dahart]

> Nurbs or any smooth geometry needs to be subdivided too

Not true; lots of smooth surfaces, including NURBS, can be and are ray traced without subdividing.

> Polygonal geometry, even subdivided, is typically not a big part of memory or time in rendering in all but the most pathological cases.

I don’t buy this either, speaking from experience using multiple commercial renderers. It is true that texture is larger, but not true that polygonal geometry is not a big part of memory consumption. RenderMan, for example, does adaptive tessellation of displacement mapped surfaces because they will run out of memory with a uniform displacement.

The balance of geometry vs texture usages is also changing right now with GPU ray tracers, and geometry is taking up a larger portion because it has to be resident for intersection, while textures can be paged.

[BubRoss]

> I don’t buy this either, speaking from experience using multiple commercial renderers.

It of course depends on exactly what is being rendered, but typically texture maps of assets for high quality cg are done at roughly the expected resolution of the final renders (rounded to a square power of 2). Typical assets will have three or four maps applied to each group of geometry, with higher quality hero assets having more groups.

> RenderMan, for example, does adaptive tessellation of displacement mapped surfaces because they will run out of memory with a uniform displacement.

It is specifically screen space displacement and this has been effective, but was originally crucial in the days where 8MB of memory cost the same as someone's yearly salary. In PRman actually polygons are even less of a burden on memory because of this with micropolygon and texture caches for efficiency, even with raytracing.

The real point here though is that nurbs don't really have much of an advantage, even in memory, because polygons are already lightweight and can be smoothed. Subdividing of polygons is typically not going to be too different from burbs and heavy polygonal meshes are likely to be extremely difficult to replicate with nurbs.

Don't get too caught up in exactly what is technically possible, this is about why nurbs are not an ideal form of geometry that anyone is trying to use again. Their disadvantages outweigh their advantages by a huge margin.

[berkut]

> Polygonal geometry, even subdivided, is typically not a big part of memory or time in rendering in all but the most pathological cases. 4k would still mean that one polygon per pixel would be 8 million polygons, which is going to pale in comparison to texture data typically.

Erm, at VFX level at least, that's not really true: once you have hero geometry that needs displacement (not just bump/normal mapping), you effectively have to dice down to micropoly level for everything in the camera frustum. And with path tracing (what everyone's using these days, at least in VFX), geometry caching/paging is too expensive to be used in practice with incoherent rays bouncing everywhere. Disney's Hyperion renderer does do that, but it spends a considerable amount of time sorting ray batches, and it was built to do exactly that.

Image textures, on the other hand, can be paged fairly well, and generally in shade-on-hit pathtracers (all of the commercial ones), this works reasonably well with a fairly limited texture cache size (~8 -> 16 GB). Mipmapped textures are used, so for most non-camera rays that haven't hit tight specular BSDFs not much texture data is actually needed.

Once things like hair/fur curves come into the picture, generally geometry takes up even more memory.

[BubRoss]

The original thread was about nurbs not being used anymore over polygons. Displacement doesn't change the equation between polygons and nurbs of course because they both go in as high level primitives. Hair is a its own thing of course. I know you know this, but I think a lot of people missed the original point.

[michal_f]

3delight also traces SDS and nurbs analitycally. In offline renderers geometry data constitutes to most of memory usage. Texture RAM usage is kept under a few GB by use of page-based cache.

[BubRoss]

Multiple gigabytes of geometry is a lot. That ends up working out to potentially dozens of hundreds of polygons per pixel. Even so the person I was replying to seemed to wonder why everything converted to polygons, which is because of a more holistic pragmatism.

[berkut]

Now try it with displacement :)

Agree in general about geometry memory though: in high-end VFX, displacement is pretty much always used, so you have to dice down to micropoly for hero assets (unless they're far away or out of frustum).

[dahart]

This seems like a strange way to frame it. Polygons aren’t what get subdivided. Subdivision surfaces & NURBS are what get subdivided, and those are routinely used in production and have tooling. Polygons by themselves don’t get any smoother or provide the advantages you’re talking about, nor do they solve all problems of workflow, tex coords, stitching, etc.

[holoduke]

You can apply subdivision on any type of geometry. Even voxels. Tesselation is also a form of subdividing.

[dahart]

You certainly can, that’s true. But without a higher order source model to work from, it doesn’t help you solve any of the problems @BubRoss mentioned above.

Tessellation is not just subdividing; it’s linearizing something else. You have to start from that something else for tessellation to be meaningful. The GP comment above was advocating polygons as a replacement for curved surface representations, but without a curved surface representation like a subdivision surface, tessellating polygons doesn’t make a lot of sense.

[BubRoss]

I'm not advocating, I'm explaining why it already happened twenty years ago. Polygons can be trivially subdivided to a rounded surface or converted to a subdivision surface. This is something anyone who has used maya, houdini, lightwave, softimage or 3D studio has seen their entire career.

If you think using polygons solves no problems, I'm guessing you haven't tried to make a pipeline with nurbs (not many have in this day and age). Texturing takes specific paint and texturing tools while the resolution difference between patches complicates things even further. Even getting the model detail is difficult. Everything about it is painful. It isn't even a contest, everyone transitioned to polygons and no one looked back.

[zodiac]

You can have physically based rendering with those non-triangle primitives too!

[weinzierl]

You can have, there is just no renderer that supports it, or is there?

[zodiac]

IIRC pbrt and renderman do

[ginko]

Even in 2013 this wasn't really the state of the art anymore. LuxRender came out in 2008.

[the_cat_kittles]

i dunno, i found it pretty good for making a big 3d datavis- shameless plug: https://somestuffforyoutolookat.ml/pages/hourly_carbon_la.ht...