Rendering stops at 18%- material issue?

[Speedster]

Hi all;

I've been posting a lot, so I hope you can put up with another one!

I am having a rendering problem, and not sure whether it's a material or render issue.  The project photos are below, as a screenshot and a rendered out clay pass. 

The render hero shot stops at 18%, regardless of size.  A 500 wide stops at 18%, as does my target of 6000 wide.  The 500 reaches 18% in about 3 minutes, and the 6000 at about 4 hours.  Running a dual quad-core, or 8 CPU's.

The first attempt was a legacy .bip.  When this crashed, I opened a fresh KS file and imported the model again, starting from scratch, but using the same materials.  I had saved the materials to a new library tab.  Both files behaved the same, stopping at 18%.

The .bip is 199 MB, with 2,190,956 polys.  Frame Rate averages 34.2.  All settings are as I usually use without any problems.  Shadow Quality: 1. Ray Bounces: 6.  Samples: 16.  Anti-alias: 1. Pixel Filter: 1.5.  High Quality Texture Filtering unchecked.  All pretty standard.

Now, I think it's the black material, as the clay pass rendered 1000 wide without issue, in about 3 minutes.  "Black" is 'Metallic Paint', Roughness 0.3, Metal Roughness 0.05, Metal Coverage 0.75, Metal Samples 16, and IOR 1.4.

Any ideas would be greatly appreciated!

Thanks,
Bill G

[Speedster]

Update- Thinking that the issue may be with a Metallic Paint, I repainted all the black with a new "Basic Black", a General material, and tweaked only the specular setting.  Tried again, as a 500 wide render.  Locked up at 17%.  Sheesh!  Here's a screenshot.
Bill G

[guest84672]

This seems strange - if it was the paint then I would think it would lock up right away. Are you using a bump somewhere that may take a while to render?

[Speedster]

Hi Thomas;

No, there's no bumps that I know of.  Window "glass", and some metals.  Always stops at about the same place on the geometry (middle of the cab side window), which reads as 18% regardless of render size (500 or 6000)- otherwise, everything's pretty normal.

I've rendered many other similiar projects (poly count, file size, materials, etc.) without problem.  What's puzzling is that the clay pass roared right along as usual.  So I don't think there's a geometry lock or corruption, especially since it acts this way on both the legacy and new .bips.

Not sure how to read this.  On the "Render Progress" window and progress bar that pops up, expanded to Details, the clock, of course, keeps ticking.  The memory Usage does as well, until 18%, when it slows down to like 100 or so increments in about 5 minutes.  Come back an hour later and it's only increased by maybe 300-500 thingies. 

Bill G

[Robert V.]

What you could try is using region rendering. Split the picture in many tiles and render those separately (This also works for people with memory issues). Combining the tiles shouldn't be a problem with a standard photo-editing-program.

I would choose tiles with the size equal to what keyshot was able to render in your "18% render".