Chromium Plated Problem

Hi folks

I’m having more than a few problems with chrome (yes I know it’s been done to death in these forums already but as far as I can find this particular problem hasn’t been looked at before)

I’m modelling a spoked motorcycle wheel (early WIP stages) and I’ve ground to a standstill trying to make chrome spokes. The best I have managed as yet is shown below (ignore the rest of the render, like I say it’s early days)

I know the rim and hub aren’t particularly ‘chromey’ but they’re meant to be polished alloy :wink:

The problem is in the spokes. I can’t get them to look anything like chrome at all, even with a shader which produces perfectly acceptable chrome on the rim and hub. I’ve tried every combination of shading and rendering and modelling I can think of but still can’t manage it (this has taken me weeks so far!)

Even rendering in Yafray after much tweaking the results are far from perfect, but are a huge improvement nonetheless.

As you can see, the hub and rim in this test render of an earlier version of the wheel are perfectly reflective but the spokes look, well, unpolished (Though this may be just because of the background I have chosen to use and/or lighting - it was just a test ;)).

If anyone has any ideas as to how I can get a nice chrome effect on my spokes in Blender I’ll be eternally grateful. And while I’m at it, if anyone has a nice set of shader settings for polished brass :wink:

Oh, btw, just in case anyone has ever come across this problem rendering…

Don’t use ray traced shadows on the illuminating lamp (took me ages to figure that one out)

Thanks in advance


did you try turning on the unified renderer?

Yep, I think that by now I’ve tried every damn button in Blender :wink:

I did an extreme close-up view of the spokes and it would seem that the problem may lie in the ray depth. They seem to be reflecting quite nicely, but the reflection is very grainy when you get in close. A lot of black spots in there - similar to the ray-traced shadow problem above but on a MUCH smaller scale.

I’m guessing that what may be happening is that the ray tracer is coming to its limit (10) and leaving a black spot at the end of the path, which breaks up the reflected image. Then when Blender oversamples it merges these black spots into the reflection and this is what takes the sheen off the chrome. Same thing happens if you try to render at 4x size, then anti-alias the image in post processing.

I have a nasty feeling that the only answer in my case would be to boost up the depth of the ray trace (the Yafray image was at a depth of about 250 or so - which had little impact on rendering time surprisingly enough). Unfortunately Blender is limited to a depth of 10 (unless someone knows a way to get around this).

Hopefully someone will prove me wrong soon though :wink:


ray depth is basically the number of bounces that the ray makes - in this case, it would probably be no more than 2-3…

If the problem is only occuring when the spokes are sub-pixal to 5 pixal or so sizes, then it could be because the renderer is not shooting enough rays at them, and their only reflecting light/background from one direction, which isn’t all that useful in this case…

Otherwise, ummm… dunno