OTOY Forums

Hi all

Im currently building a bottle that will have faceted groves in the glass and although I could model it, its simpler to use a displacement map as the geometry will get complicated at certain areas.

Im not sure though if something odd is going on with the displacement itself? See screen shot attached. I had to add gradients into the vertical sections to simulate the bending in within the facets but its doing something weird and messing up the texture so it looks like there is a noise bump map happening at the same time. I cant work this out hence coming on here in the hope that someone can help point me in the right direction. I've also tried using the vertex displacement node but it doesn't work that way either.

Thanks for any help.

it would appear to be in your map itself. How did you generate the map?

Thanks jayroth. I did it In Photoshop. It seems to not like the gradients for some reason so would you recommend another way to do it? I did start in Illustrator but then exported to PS as thats my usual way.

I ran the main panel disp v4flat.tif map through the HDR tonemap filter in photoshop until I couldn't see any steps in the blends. I can only get so accurate, as I do not have an HDR monitor (which would come in handy to definitively debug this). Even so, just doing that helped tremendously. Make sure that your map is set to 32bit color depth in PS. When I loaded it, PS said it was 8bpc.

Once you have the map back in Octane, make sure that you set the float type to 32-bit float. If necessary, you can also do a little filtering in the displacement node. I typically use a box filter set to 1.5 radius. Set the gamma of your map to 1 as it is 32-bit float without any grading.

I also adjusted your materials a bit: I enabled fake shadows on all of the transparent materials, corrected your smooth shading angles (which was causing a discontinous artifact on the upper bottle section) and added an OctaneObject tag to the liquid object. Also, I use the OctaneObject tag for subdivision, as it is far more efficient than using the SubD generator. You can still use that if you want, but just set the render subdivisions to 0 and let the tag do the work instead.

Lastly, I set the camera imager response to linear, natural response enabled, and gamma to 1. You can always grade after the render, but this will give you a clean starting point.That will get you past most of the issues you are having with this scene. To make the displacement as artifact-free as possible, you would have to redo that map. That said, if you look at real glass bottles, the manufacturing process adds plenty of little defects to the glass itself; if your render is too perfect, it won't look real. Of course, if you want a stylized look, that could work out for you.

A final note: you are using a Cinema gradient on your background plane. Try using the Octane gradient as an option to get cleaner results.

yes, if you are using Illustrator, I would output directly from there if you can. Make sure you output to 32bpc color depth. That will give you the best results.

Nice looking bottle! Good luck!

Thanks jayroth thats really great info, much appreciated.