[berkut]

Drawing lines is a stupid way of doing it, as:

1. With the mess of overlapping lines they've got, you'd suffer from severe overdraw (which is where raytracing really shines in terms of efficiency) as you can't efficiently cull lines (without clipping them)

2. You wouldn't get the ambient occlusion look where lines close to each other occlude / darken.

As someone who's previously compared Embree and OptiX (and we were given free hardware and support from Nvidia), Embree stacks up really well, and a dual Xeon can match a single top-of-the-line GPU fairly easily for pure ray-intersection performance.

Once you start putting complex shaders and layered materials on top, GPUs start to really suffer: there's a reason a lot of the GPU renders are mostly being used for clean renders like archvis / product design / car renders - they're simple to render. As soon as you stick dirt layers on top, their efficiency really starts to plummet.

[doctorpangloss]

> stupid way of doing it

I guess it really depends on what the objective is. I'm not talking speculatively, but concretely it seems like a reasonable way to achieve a few images that they show in the press release. They show two relatively flatly rendered lots-of-tubes images. I know SSAO isn't the same, and I get that there's overdraw, but there are a lot of details in the particular objective they want. In one shot, they show a lot of emissive tubes with depth of field, which is harder to achieve. I suppose if they're happy, they're happy.

> interactive performance for all datasets on a regular Intel Xeon processor, which can render images at 20-25 frames per second (FPS)

There's a big difference between interactive performance and a production-quality render. Something tells me it's not producing 25 frames of noise-free render per second. There isn't enough information here.

> and a dual Xeon can match a single top-of-the-line GPU

At what, like 3x-5x the price? At how many watts? And at what I.T. complexity? A GTX 1080, at better performance than a Titan X, is really a phenomenally good deal. Especially considering I can drop it into an existing workstation with all of my existing software installed on it; especially considering I can rent out computation time on Amazon by the hour.

I guess what I'm reacting to is how forced of an example it seems.

[berkut]

I think the objective is rendering a ridiculous amount of stuff - the fact they talk about "lots and lots of RAM" indicates there's no way a GPU is going to be able to render it efficiently without an aggressive culling step: GDDR5 might be very fast, but you've got to get the data onto the GPU first and probably page data as well. This is very often a significant bottleneck for GPUs, and is another reason GPUs aren't used for VFX rendering (at high-end), as 16 GB isn't anywhere near enough.

Production-quality render implies decent lighting and materials - this stuff has neither, so shading is likely to be negligible, and then you're going to be generally constrained by ray / primitive intersection performance.

No, cheaper (for CPU) : two ~$950 CPU cores vs $3,300 GPU. Granted you need a dual-socket system and twice the RAM to balance and it's easier to stick multiple GPUs in a system than make the jump to 4 sockets, but GPUs aren't really that much of a win... Thermal output and power usage is often worse for GPUs as well.