PDA

View Full Version : Lightwave getting odd results with a normal map from Gaea



starbase1
11-09-2019, 07:23 AM
Hello All,
I've been having a lot of fun with the Gaea terrain tool, exporting displacement maps and textures for rendering in Lightwave.

I've just started trying the Normal Map build from Gaea, but I'm getting odd results.

To be specific, I'm getting bright areas on some cliffs, acting like they've received a serious boost in diffuse.
On examining the map, it has some green areas which look to be on the cliffs, whereas I normally expect the colours to be dominated with purple, and a bit of red and blue.

I attach a smaller version of the map.

Is this some flavour of Normal map that LW doesn't like?
(The original is 8k x 8k, PNG format, 16 bits per colour channel).

Any ideas on how to work around this?
Maybe editing the map to remove the green, or perhaps to generate a new one from a 16 bit bump map?

Any software solution needs to handle 16 bit channels and BIG images.

Thanks in advance for any suggestions,
Nick

PS - I'm still mainly using Lw 11.6

Kryslin
11-09-2019, 08:24 AM
Using the map you provided, in LW2015 (earliest version I still have installed), I didn't see the issue you described.

However, doesn't mean it doesn't exist - mainly because jpegs are 8 bit per channel images. Maybe the solution lies into using an image format that use floating point data, like .exr?

starbase1
11-09-2019, 08:36 AM
Could be...
But as I said, I don't normally see the green, so I think there's something else going on with noirmal map flavours.

Thanks for the suggestion,
Nick

erikals
11-09-2019, 09:05 AM
hi, looks to be a World space normal map, (or Object space) rather than Tangent space normal map...

https://gamedev.stackexchange.com/questions/61221/why-dont-we-use-the-whole-color-depth-for-normal-maps

starbase1
11-09-2019, 11:01 AM
Ah, thanks for that.

And judging by Google, there's a DP kit node to handle the conversion!

erikals
11-09-2019, 11:07 AM
 https://i.imgur.com/fMb2Mjm.gif

dpont
11-09-2019, 11:20 AM
I don't know the original displaced terrain,
but looks like a correct normal map in tangent space,

146257

You may be surprised by red or green color in it,
this is because the relief is heavy,
so the normal of a flat surface is heavily perturbed,
also commonly it is of course better to displace
the flat surface with a height map.

Denis.

erikals
11-09-2019, 02:24 PM
Wow, never thought that would've been Tangent. https://i.imgur.com/4UKo6V4.gif

starbase1
11-10-2019, 05:52 AM
Hi Denis, and thanks for the response. You know more about this stuff than me.

However in this case I'm not convinced - I think the "bad" normal map is close enough to have a normal map like effect.

I attach two VPR views of the scene, the only difference is that normals are off in one case,

146263

While it definitely adds roughness, there are the weird bright patches on the cliff face.
So I suspect that the others are correct, and it's a different type of normal map from what Lightwave is expecting.

Nick

erikals
11-10-2019, 06:14 AM
not sure, it is either an extreme normal map (where a displacement map would provide a much better result)
or, like stated in post #4, a World space normal map, (or Object space) rather than Tangent space normal map.

do check / ask over at the Gaea forum.

dpont
11-10-2019, 09:18 AM
...While it definitely adds roughness, there are the weird bright patches on the cliff face.
So I suspect that the others are correct, and it's a different type of normal map from what Lightwave is expecting...

When you have different type of Normal map, like different space
of axis inversion you get garbage, not the case in my test,
but you may have other kinds of error in the mapping itself,
don't know how you applied it in Lightwave.

Denis.

dpont
11-10-2019, 10:12 AM
Wanted also to verify if the faked relief above was convincing (without knowing the original)
not a great resolution but I'm able to get a rough height map,

146264

and a displaced mesh object;

146265

Edit: Normal to Height done with AwesomeBump application

Denis.

starbase1
11-10-2019, 11:47 AM
Interesting! That looks like a negative of the actual displacement map!

starbase1
11-10-2019, 11:49 AM
Well, the way I am doing this is a have a 4k x 4k EXR displacement map. I have this producing about as many polygons as my 32Gb memory can hold.

So my plan is to try adding a higher resolution normal map, (currently trying 8k x 8k), to get an extra level of detail.

dpont
11-10-2019, 11:57 AM
Interesting! That looks like a negative of the actual displacement map!


So in this case Gaea seems to not have the same Y axis than LW,
this can be adjusted in LW, try "invert Y" in the normal map node.

Denis.

rustythe1
11-10-2019, 12:40 PM
if your using 2018-19 did you remember to change the colour space of the map, in the image editor? you need to set normal maps to linear,

starbase1
11-11-2019, 02:34 AM
Thanks Denis, that was it, flipping the Y in lightwave gave a sensible result!

Perhaps the normal map was rotating the polygons effective angle to where it pointed downwards?
Whatever, I now now how to fix it.
146271

And incidentally, I really like Gaea as a terrain tool. Node driven, really easy to make and tune landscapes.