OTOY Forums

I am trying to convert a model I have that uses some fairly complex layering of bum maps.

In Lightwave, you can increase the effect of the bump quite a bit and it works really well.

I have sussed out how to increase the effect of the bump in Octane's nodes, however, I get that crappy problem with the shadow terminators being solid (Aaargh).

So, I think, convert the bump maps to Normal maps.

Done that, now trying to figure out how to increase the effect of the normal map.

Have tried increasing the Power, changing the Gamma in the Texture Node. Have plugged in a Colourcorrect node (how I increased the bump strength). That actually makes the normal dissappear.

Help, what do I need to do to get a good looking bump, that I can increase way beyond 1. I have the thing that will convert bumps to normals, but then how do I increase the Normal strength. Help.

I'm posting this in the Lightwave forum also.

Hi Gordonrobb,

The gain of bump maps can be adjusted because they are simply passing the renderer a value with which to perturb the surface normal where as a normal map is actually giving the renderer an explicit value for the normal, that doesn't mean you can't change the gain of a normal map but it doesn't make sense in quite the same way as it does for a bump map.

Either way you will still have the same terminator issue with a normal map as this is unfortunately a known issue in Octane that affects both bump and normal maps as detailed in this topic http://render.otoy.com/forum/viewtopic.php?f=33&t=37648

T.

Cool thanks. Had read that post but thought it was only discussing Bump maps.

So how do you increase the gain of normal maps?

gordonrobb wrote:So how do you increase the gain of normal maps?

If you created your normal maps from bump maps you should be able to go back into photoshop or whatever software you used and there should be a setting for depth or something close that will allow you to write out new normal maps that will give more effect when used in the render.

The reason you can't just increase the gain of a normal map as a post process is because a normal map uses the R, G and B channels of an image to provide a new normal vector to the renderer at any given pixel. So to change the "amount of bump" you actually need to change the proportions of R, G and B for each pixel, and not all pixels would need to change by the same proportions.

I hope that makes sense, it's a little hard to explain in a short post.

T.

Makes total sense, and is a total pain. With bumps I can have one image in different places with different depths. Hope they do something about fixing that shadow terminator crapiness.

Try this to up a Normal map's intensity - open the normal map up in Photoshop. Then duplicate the layer of the normal map. Set the duplicated upper layer which you just created to Overlay mode. Flatten the image and save. This may take some experimenting, but it's worth playing with normal maps in Photoshop to figure out some tricks.

Photshop's Overlay mode is pretty useful for combining multiple normal maps into one. To get around Octane's limitation of not being able to use bump and normal maps together, I'll often convert the bump map in question to a normal map (using the lovely program xNormal), and then combine my new normal map with the older normal map in PS.

Hmmm. I'll take a look.

To get around Octane's limitation of not being able to use bump and normal maps together, I'll often convert the bump map in question to a normal map (using the lovely program xNormal),

You can use Bump and Normal together : Duplicate your material and create a mix node. Use Bump on the first material, and NRM on the second one. But if you have 0.5 as mix factor, each setting is at 50% and the result is not stronger. We would need a Math node with Add or Multiply...

You can change the strength of the normal map by changing the power slider on the image texture. If you need more strength you can set this one to more than 1.0 by using the arrows or using the numeric input.

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Roeland

Hmm. Need to try that. I didn't think it made any difference above 1. I'll give it a go