Highpoly artefacts on normals ?

repete

Hello all

Having a job with normals for a box, modos lack of smoothing options :poly122: is an arse for starters and using a cage file in xnormal is a no go on a box.

The bake looks ok just using ray distance in xnormal:



but it looks like the highpoly is causing the artefacts (max zoom in ps):




and the result:



I know that this type of hp to lp baking is a pain but that's why I am doing it, lots to learn from it !

Cheers for any help on the matter

pete

underfox

I don't know if this would work but what if you selected each cube in photoshop and applied a really subtle gaussian blur to it?

BARDLER

underfox wrote: »

I don't know if this would work but what if you selected each cube in photoshop and applied a really subtle gaussian blur to it?

Never ever ever do this.

First off, somebody made a vertex normal plugin for Modo 701, http://www.polycount.com/forum/showthread.php?t=122073

Second, you can use a cage even for a box, I am not sure why you think you can't.

Third, can you post your UVs, lowpoly, and highpoly. The artifacts could be any combination of those three things so its hard to say.

On a side note it could also be a compression issue, what file type are you baking and saving as?

underfox

Would you please tell me why it's not a good idea, I'm not doubting you, I just want to learn why so i don't do that mistake for future works :P

BARDLER

underfox wrote: »

Would you please tell me why it's not a good idea, I'm not doubting you, I just want to learn why so i don't do that mistake for future works :P

You should be able to get the correct normal map out of the baker every time if you are following the right practices. The need for photoshop for fixing normal maps is because of a lack of understanding and bad techniques more then anything. The only time you should use photoshop with your normals is adding small details in nDo2 or with height to normal operations.

Normal maps are tough to understand at first, I know the feeling all to well lol, but putting the time into learning exactly what is going on helps tremendously.

The first page of EarthQuake's thread covers this perfectly.
http://www.polycount.com/forum/showthread.php?t=81154

underfox

Your the man. Thanks for the link, carefull reading awaits me

repete

Thanks all

you can use a cage even for a box, I am not sure why you think you can't

Of course you can use a cage on a box but you get distortion and the closer to the edges the worse it gets, so adding any details to the side faces will have bad shading errors.







Using 2k tga !

SeenFarfarer's vertex normal toolkit but I want to know first why these problems occur for my self before I start running scripts to fix them, I can't learn that way. I see many tutorials on the subject of "box normals" but never see a high gloss material added to the end result and I see many different opinions on this type of box baking, some say do option A another option B. Baking normals imo is a science and the link below shows it:

http://www.chrisalbeluhn.com/Normal_Map_Tutorial.html

I will continue testing this !

Steppenwolf

What file format you use for your normal bakes? I used to get artifacts with obj files in xnormal. Only use sbm files nowadays. Was probably one of the export options messing up the model but i'm no expert on that one. At least sbm works fine for me straight out of the box.

repete

I tried sbm, no joy but I now know that the high poly mesh has smoothing errors in it and this is bad news if modo can't even export a high poly without errors.

I isolated and zoomed in on the red channel on the normal map and you can clearly see the stepping on the curvature of the high poly which is causing the shading errors:



Upped the polys to 393216 and still get the above errors.

Testing continues :poly122:

Zenoart

Can you try to separate the different faces of the box in the unwrap?

I did a similar test in 3dsmax a few years back:

Box, no chamfers, 1 smoothing group: Bad
Box with chamfered edges worked well, no need to split UV's: Good
Box, no chamfers, different smoothing groups and split UV's: Very good

With the last one I managed to project one face of the cube and use that result on the other faces of the cube without any seams.

BARDLER

I would recommend having more edge padding on your shells and spacing them further away from each other. This isn't causing your issue, but it will cause different issues down the road if you keep them so close to each other.

You need to use that script in Modo to bake correct normal maps, and if you don't there is know way of knowing how Modo is weighting your vertex normals of your lowpoly. You need to set hard edges on every single face since each one is a unique UV island, this is what gets normal maps to bake properly.

One of two things is happening. Modo isn't assigning the correct vertex normals to your lowpoly or highpoly, and the banding is coming from that. You need that vertex normal plugin to fix it and assign hard edges to your lowpoly, and soft to your highpoly.

The second thing that could be happening is image compression. If you bake out a tiff in xnormal you get 16 bits instead of the 8 bits from a TGA. This will give you larger range of colors in the map, then in photoshop convert the 16bit image to an 8 bit image.

First you NEED to download that script, and use a cage. If you want to prevent details from skewing then be smart with how you design your lowpoly, and read Earthquakes waviness thread in normal maps. Not using a cage, is the worst solution to that problem.

repete

Thanks guys

This might take a while