Emulating soft edges on hard-edge models? (Possible?)

adam

Hello

I swear I've worked with an engine that has this capability in the past and I am hoping you folks can help me find out the name of this technique, so I can read up on it.

Have you ever seen or worked with tech that could control edge softness right in the engine? So if I have a hard edge in Max on export (each face is a seperate smooth group, for instance) the engine can emulate a soft edge?

Source can do this with BSP, but I am not sure how is done and assume they just cut the BSP with additional edge loops.

So if you imagine making a simple 6 sided cube where each edge is hard, you'd be able to tell the engine to render those edges soft (as if they're rounded or beveled) and from there control how soft or hard it is.

rumblesushi

I don't know how source does it, but I can only imagine it would be dynamically adding edge loops, like chamfering each edge with a few segments.

Did you want to do this as a sort of LOD method? Like softening the edges as the object comes into view?

adam

No I want to be able to make hard edge objects, no highpoly, and make their edges look soft.

hijak

http://deadlineproof.com/model-shading-techniques-soft-edge-superspecular/
think this is what you mean

pior

Hijack : I dont think so hehe. Its a great technique but I think Adam means something else.

Adam. For starters you can check some solutions already available for regular renderers. Max used to have a plugin exactly for that, and now MentalRay has an architectural shader doing exactly this too. (ever monder how come shitty arch wiz models look great when rendered? Heres why!)

I have seen it done realtime too, kinda cool.

As for hacking it manually : render the hard edged lowpoly into a smooth edged lowpoly, and have fun blurring the edges in photoshop!! Works great.

Hope this helps!!

adam

Hijack - So is he just chamfering edges to get that look?

pior - can you elaborate? I'd like to have a few links handy if possible.

rumblesushi

adam, I would think that's impossible. If an engine does that, it's simply adding more polygons around the edges, like a very basic version of dynamic tesselation.

commander_keen

You could do it with a combination of render to texture (to get blured screenspace normals and depth), and a tricky pixel shader for the object.

Piflik

Max' Arch&Design Materials have a Round Corners feature. It's somewhat like a Bump Map, only a trick of shading, no real silhouette changing...and only for offline rendering with MRay...but it could maybe be incorporated into a realtime shader...

rumblesushi

A shading trick would only go a certain way to making those edges look round though, at certain angles, you'll still clearly see they are hard edges.

Peris

in source is done with the lightmaps on bsp. I think that's what you mean at least, if you give two bsp faces the same smoothing group it will create a big soft look to the edges.

MoP

I don't really understand why you wouldn't just do this in your 3d modelling package?

Unless you're talking specifically about BSP geometry created in an arbitrary level editor.

ralusek

hijak, all that guy is doing is adding a bevel, and then applying a "normal modifier" to average the normal of each main face. i don't understand how that applies to an export from max though. how is that information going to be passed to an engine as a modifier, all i see him achieving is either a fully smoothed beveled object, or one with a combination of smooth/flat shading. but still, i'd be curious to know if he is successful in exporting this somehow

MoP

ralusek: That technique will work fine for any exporters which preserve per-vertex normal information. Some do, some don't, depends what game engine and file format you're using.

Eric Chadwick

Here's what the mr Architectural Material Round Corners thing looks like.

Anyone remember f-edge? It was also a renderer-only solution.

Might be too expensive for in-game use, not sure.

hyrumark

Check out the article in the book Shader X5 called "Micro Beveled Edges". This does what you're after on an engine-level.

Basically the engine calculates two sets of normals per model, the first set is the hard edges, the second set is smoothed normals. Then it masks the edges of the model, displaying the smoothed normals at only the edges, and the hard normals along the flat faces. Giving the model a beveled look without the bevels, and without a normal map.

EarthQuake

stop being lazy, do some proper HP work you slacker.

MoP

hyrumark wrote: »

Check out the article in the book Shader X5 called "Micro Beveled Edges". This does what you're after on an engine-level.

Basically the engine calculates two sets of normals per model, the first set is the hard edges, the second set is smoothed normals. Then it masks the edges of the model, displaying the smoothed normals at only the edges, and the hard normals along the flat faces. Giving the model a beveled look without the bevels, and without a normal map.

Hmm, interesting. How expensive is that technique? Would be interesting to know if it was actually more efficient to just bevel the edges instead of using a shader, or vice-versa...

hyrumark

The main argument made in the article was the speed of asset creation using this technique, mostly for simple "non-hero" environment assets. No need to tediously model and UV map chamfered edges for EVERYTHING, basically you get the soft edges for free without extra geomety or having to bake a normal map. Less expensive technique than traditional normal mapping according to the article.

I've not used this technique in a shader myself, I just thought it was interesting as well.

rumblesushi

That does sound interesting actually, do you know of any videos hyrumark where I can see the technique in action?

yiannisk

direct X 11 now support subdivision on the fly.
i think we are going to see it more and more.

i was watching a video the other day showing this in a game currently in production that takes advantage of this technology but can't remember which and can't find it now.

maybe you mean something like that ?
[ame]http://www.youtube.com/watch?v=bkKtY2G3FbU[/ame]

rumblesushi

No, I think he is talking about a shader technique, especially seeing as it was of an engine that he worked on previously, ie not a DX11 game in production.

pior

Yian I think you are thinking of the new AvP

yiannisk

i was looking further later and i found out that the latest Dirt also features that technology.

also look what i stumbled upon. this guy is talking about point cloud data technology.
it is quite interesting. he talks in layman's terms at least early on but this actually could be the future.

Polygons is only a way to manage complexity because we need to at the moment after all. People seen lots of technologies fly by understand this. Those who were born and grew professionally in the polygon generation might find it a bit unbelievable.

Unlimited Detail Technology
[ame]http://www.youtube.com/watch?v=Q-ATtrImCx4[/ame]

there is also part 2

[ame]http://www.youtube.com/watch?v=l3Sw3dnu8q8[/ame]

rumblesushi

yiannisk - there's a whole thread on that in general discussion.

What did you found out about the latest Dirt game?

pior

lol

yiannisk

that's nice, are you talking about tessellation or unlimited detail?
glad there is already a thread, i'll go check it out!

regarding Dirt, i found this.

[ame]http://www.youtube.com/watch?v=fEC0WAF2NIg[/ame]