Questions about hard surface modelling with mesh smooth...

sp0nge

Hey guys,

I'm modelling some weapons for a MOD in it's early, early stages and have decided it's time to sort out a problem I've had with hard surface modelling for a long time...

Basically, as the pictures show, simply chamfering the edges creates this dodgy pinching effect in the corners where it meets the round barrel. I've got by with just kind of bodging in extra lines about the place before but it's always a compromise, most often damaging the roundness of the barrel itself. I'm sure there's a way of getting those hard edges to meet a round surface without nuking the curves when mesh smooth is applied and I'm desperate to find out what it is


Hope you guys can help!

Cheers,

Sp0nge

Sean VanGorder

It would probably help just to simply add more geometry to the barrel. Also, for this situation, I would manually add in supporting edges using ring and connect. Using chamfer on this just ends up giving you messy geometry.

r_fletch_r

Keep in mind that those sorts of features in reality are not part of the same piece of metal. I cant tell in your case as you dont show the reference but usually there is a fine line of weld, a notch the site fits into or a ring of metal around the barrel that keeps the site in place.
For Hard Surface its allways a good idea to break your mesh up as much as you can, if its logical and if it fits the reference.






if its essential to make it as one mesh id increase the number of segmetns of the cylinder to keep deformations in a localised area.
also looking at your mesh you seriously need to clean up your bevels. Theres is nothing wrong with using chamfer, you just need to do it a loop at a time. clean up the little funny bits and then the the crossing loops. if you do them both at the same time it becomes a bit of a cluster fuck

sp0nge

Hi guys, thanks for the comments. DW too much about the tangled fishing net look of that chamfer, was just a quick way of showing what i meant the pinching occurs no matter what kind of clean up i do. Also, unfortunatly this part actually appears to be part of the same metal as the barrel on referance images

by adding more geometry to the barrel do you mean like the blue lines in this pic or the red lines or both? I assume this would basically take the pinch down to a neglagble size rather than remove it?

cheers!

bbob

You just need more segments around on the barrel, blue but all the way around, otherwise it'll look wobbly. You might also want to make your chamfers a lot more loose otherwise your gonna have a hard time seeing them on your normal map..

sp0nge

cool guys, cheers for the help - adding in more sides to the barrel cylinder has pretty much got rid of that pinching!

@bbob: how do you mean more loose? you mean like a larger chamfer to get a smoother edge? It's pretty much a very sharp edge on these parts when I look at the reference so I'm not too fussed if it looks sharp on the normals eventually? is that what your talking about? i dunno

Ark

If your chamfers are really tight, they won't show up in your normal map when you go to bake, especially if you only baking to something like a 512 map.

bbob

What you have to remember is that normal maps records directional data and not depth data, so if your chamfer is so tight that it doesnt register as a pixel, you will not see anything. So keep your mapsize in mind when modelling.

Sometimes you have to twist reality to your needs

sp0nge

you make a very good point, I'll revisit the chamfers and try and open it up on the detail a bit

I'll post some updates when I get a little further on, cheers for all the help chaps

sp0nge

x

maxivz

would you mind posting a screenshot of a wireframe of the chamber? i always had problems with trying to make one turbosmothed. I will really apreciate a the scrrnie, thanks

CapN

One thing that you can try is deleting your turbosmooth modifier, convert the mesh to an editable mesh, then covert the mesh to an editable poly, then reapply the turbosmooth modifier. I am really not sure why it is but on occasion I have had max do some odd things with smoothing and somehow going through this process changes the smoothing and can make it less harsh. This has also worked for me in the past when max would smooth areas incorrectly i.e. when max subdivides areas incorrectly even though your topology is fine.

maxivz

One thing that you can try is deleting your turbosmooth modifier, convert the mesh to an editable mesh, then covert the mesh to an editable poly, then reapply the turbosmooth modifier. I am really not sure why it is but on occasion I have had max do some odd things with smoothing and somehow going through this process changes the smoothing and can make it less harsh. This has also worked for me in the past when max would smooth areas incorrectly i.e. when max subdivides areas incorrectly even though your topology is fine.

Hey, thanks for responding, but my problem is not about weird smothing becouse of max, its weird smothing becouse of me :P, its my weird geometry, i will try redoing it and using chamfer this time, i dont use that tool very much and its really helpfull, if somebody can show me how he does that shape in the chamber of the weapon in a step by step tutorial i would be really greatfull

sp0nge

hey, I spent ages trying to get it right and no doubt it is a bit of a bodged way but ya know, it worked the low poly cage will no doubt give me a whole new set of problems when I come to make that

anyway, I started off with a 36 sided cylinder. I then made a 9 sided cylinder for the cartridge holes and rotated it around into 6 equal positions using the snap function set to vertex. I then deleted the end faces of those cylinders and flipped their faces, then just kind of borked some faces to join up the main cylinder.



for the other side, with the grooves (the front half of the cylinder) I made a 24 sided cylinder and chamfered every edge that sat between the cartridge wholes and inset them slightly to form the grooves using scale on vertex selection.





From here, it was all just down to mashing the two halves together, making sure that I effected all grooves at the same time by selecting the corresponding verts in each one and using transform tools to raise or lower them from the central point instead of moving them individually. There should be enough angles here to copy it roughly if you need to, otherwise it's just down to trial and error











As people have pointed out already, some of my chamfering is a bit overly tight so just go with what feels right. hope this helps, let me know if you want anything cleared up

maxivz

Thanks for the screenshots! They will help me a lot, now i wont have to be afraid or avoid making guns with a chamber
If you need anything, or want to know anything i can help, just tell me and i will try to help you
And, thanks again :P

sp0nge

Thanks for all your help guys, really kept this gun on the straight and narrow. Thought it a good idea to add on the final images (pre texture) to bring it all together

Here's a couple of view-port renders of the low poly using a standard dx shader:





...and here's a link to the finished high poly turn around:

[ame]http://www.youtube.com/watch?v=5-t0tVk_ezI[/ame]

P.S. this is a 3rd person mod hence the lack of too much crazy mechanical detail and the lowish poly count

cheers!

leechdemon

A tip I found (from the following video: http://vimeo.com/10941211?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Cgarena-GetAttentionInCG+%28CGArena+-+Get+Attention+in+the+Computer+Graphics+Community%29) was that, rather than using Chamfer on the edges you're trying to harden, use Connect on the edges surrounding it. If you're used to Chamfer, this is a little goofy at first, and will drastically increase your poly count (but if you're baking, w/e), but what it does is preserve all of the curves around edges. So you can get the same effect without goofy pinches created from Chamfers. Definitely watch the vid, he does a lot of really basic examples at first, but eventually explains some more difficult concepts, and fixes them very simply.

Nice pistol, btw!

Serp

Also, try extrude! It's awesome because it does the same thing as connect but faster.

Select the edge, select extrude, select 0 for heght and then drag the edges to the size you want.