# Automatic bump mapping

In the image, I know that setting Normal to a value (other than 0) in geometry will create a bump map from the texture onto the material. It works well and I'm doing this for the hair of a human model. What is the difference between positive and negative? Does one bump in one way and the other the exact opposite? (So if 1.0 bumps it outwards by a certain amount, -1.0 bumps it inwards by the same amount).

But my main question is the Bump Mapping Method and Space. What do these do exactly? I looked up on here and it doesn't specify their purposes, only shows the available options. What is the difference between these options? I found that Original method (which will for some reason disable Space) looks the best to me but I want to make sure that option is the most appropriate for the situation I am in.

• No one figure it out yet? Aug 7, 2016 at 23:53
• I did ORiginal and it broke. I did highest quality and it was the highest quality. Oct 10, 2016 at 4:09
• For space, check out wiki.polycount.com/wiki/Normal_Map_Technical_Details . Jul 2, 2018 at 18:22

As far as I see, if normal is positive light colours bump outwards and dark inwards, if negative - the other way round.

The rest doesn't seem easy, but here are some links. I think "Method" is mostly about quality: http://kishalmi.servus.at/3D/bumpcode/

"Space" should tell in which space the normal vector will be stored. But the results look strange.

Anyway - why not use cycles?

• I know cycles is much better but it seems too complicated and different. And I don't have much time to learn. Aug 9, 2016 at 2:17
• The thing I'm scared about space is I'm afraid it will make the bump map be projected from another object, thus if I move the hair, it's bump will change, which is not realistic. Aug 9, 2016 at 2:20
• Cycles is not too complicated (although it is different). Watch this and see what you think: blenderguru.com/tutorials/introduction-to-cycles Sep 9, 2016 at 0:32
• For "Method', select the quality level you need. For realtime, 'Low quality" is much faster than the higher ones. "Compatible" (for me) does not do anything. I think it's a fallback option for old Blender versions. The "space" dropdown, afaik, is only relevant for normal maps. This is why it's greyed out. For the "normal" value, you may want to try very small vaues like 0.05. Jul 2, 2018 at 9:12