Normal mapping a cylinder

Tom Ellis

Hi there,

I'm sure this question has been asked a million times before, apologies if it has.

Also, I'm a beginner... in case it wasn't already apparent.

I'm trying to create an Oil Drum, something I've never actually done which is surprising since the 'rusted oil drum' seems somewhat of a staple of next-gen game assets.

I went into it thinking it would be easy, and I've already hit problems.



Why are the indentations and top and bottom lips wavy rather than straight!

I've tried using a cage, geometry projection and also xNormal, all to no avail.

I don't really want to chamfer the edges at the top and bottom, but even if I did, that wouldn't solve the indents that run round the upper and lower sections of it.

Advice would be great please.

Many thanks in advance.

Neox

fixed

now seriously, use the search function its has ben discussed like a thousands times here

Bad Spleen

It's due to your projection cage.

check http://www.poopinmymouth.com (its not porn) Ben Mathis has a part of his tutorial that explains this issue, and how to avoid.

How did Neox get your model? I'm confused as to what his post is about.

Tom Ellis

Thanks Neox, Bad Spleen.

I had a feeling it had been mentioned once or twice.

I've managed to get it a lot closer by altering the projection, but not as good as Neox has done.

I'm guessing that was photoshop fixed Neox, would you be so kind as to point me in the direction of the thread that explains fixing a cylindrical based NM in Photoshop? I'm pretty sure you did that with more than a steady hand, and that there's a methodical way of doing it.

Thanks

Neox

easiest hting to do is just bake a flat profile and map it onto your cylinder afterwards.
what i did is just take the first pixel collumn of your cylindersides and stretched it to fit there. of yourse that doesn't always work, especially if you have more complex shapes on the cylinder... however here is a thread covering it, and i think there are plenty others

http://boards.polycount.net/showthread.php?t=65790

Tom Ellis

Thanks a lot Neox, thats a great help.

Also thanks Bad Spleen, I've just had a read through the Ben Mathis tut on Normal Mapping and there are some great tips in there.

Thanks again.

Taylor Hood

Hah, I love how we all have to say (Its not porn) to Poop's legendary site. Still funny..

TychoVII

There's also ways to fix the normal map in photoshop if you find that to be more helpful. Racer445's method (atleast his tutorial is the first place I learned it) uses the smudge tool to straighten out those wavy edges. Just slide the smudge tool back and forth along with the direction of the line and it usually smooths out pretty well.

Mark Dygert

TychoVII wrote: »

There's also ways to fix the normal map in photoshop if you find that to be more helpful. Racer445's method (atleast his tutorial is the first place I learned it) uses the smudge tool to straighten out those wavy edges. Just slide the smudge tool back and forth along with the direction of the line and it usually smooths out pretty well.

If you're going to do this, its probably easier to use Filters > Liquefy. According to Slum if you need to apply those changes to other players you can save out the mesh and load it.

kodde

There is no such thing as a perfectly normal mapped cylinder. At least not one that works in all angles. Make it work in the angle that will be viewed at the most, alternatively make it appear beveled with the methods mentioned above.

Tom Ellis

Thanks for the further replies everyone.

Ok I've got the ridges around the edge sorted, a bit of messing around in xNormal and Photoshop got them looking nice.

However, I'm pulling my hair out trying to figure out how to get the top and bottom lips looking smooth. How in the world did this guy achieve this:

http://www.jsalvador.net/portfolio_oil_drum.html

Those top and bottom pieces are like perfectly round! I'm getting very faceted circles which look horrible on the low poly.

Sorry to be such a full on noob here but I just don't even know where to start in achieving a smooth lip around the top and bottom.

Thanks

kodde

Perfectly round? I don't agree.

I posted this image in the other similar thread that Neox linked to. Mr.Salvador went with the right one, which more or less simulates a added bevel in my mind. Compare the example 2 and 3 in this image and you'll probably see what I mean.

Tom Ellis

Thanks Kodde,

When I said 'perfectly round' I just meant the top and bottom in the normal map, I agree it still doesn't look perfect on the mesh.

Well with a combination of some great help on here, far more time than I would have liked to have spent messing around in xNormal, Max and PS, I have managed to ge a semi-decent result. I think I'm gonna try and hide the little normal map imperfections left with the diffuse.

It's for my workshop WIP which is in the P&P section so pics will be in there eventually.

I can definitely say I will never underestimate the cylinder again, as I now know it has the potential to ruin ones day.

Thanks again for the help everyone!

pior

it looks good on that barrel asset for a simple reason : the little bumpy line near the top appears both on the top lid (round seen from the top, not wavy) but also on the flat cylinder side (straight)