what causes these jagged edges when rendering

[spiderman]

This is a render of lightwave render scenes 5 lws

[tcoursey]

Have you tried something larger in resolution? Seems like just a pixel issue on an angle....which you'll need more pixels to smooth out. I had a hard time at first seeing them...until I zoomed in past default resolution.

[Matt]

This is a render of lightwave render scenes 5 lws

Too low anti-aliasing settings most likely

[Tim Parsons]

This is a render of lightwave render scenes 5 lws

For this size render, I think it looks just fine.

[Exception]

Funny, I once made that scene 10 years ago
Yes, looks like you just need to turn on Anti Aliasing. Higher resolution helps to see it better.

[Dan Ritchie]

If the pixelation is on the threshold of bright areas, it's a problem inharent in CG in general. Think of a case where you have several pixels next to each other. There may be 8 pixels that have a relatively low value like 0.5ish, then there's one pixel in that area that has a super high value, like 1000,000ish. When you average those pixels (which is what antialiasing does), even though there are more pixels with a low value, the one with the super large value is dominant, causing the average pixel value to look jagged.

The answer is either limiting your dynamic range, or using a filter to better distribute the error over a larger number of pixels, ei, using a bloom filter. That's generally what happens in the real world when you look through a lens.