exporting with backfaces

[arteria]

Hi,

Is there a way of exporting with the backfaces of an object? I have a Helment for a knight i am working on, and i need the inside of the helment to show faces, so it doesnt look transparent when the model is wearing the helment. I have tried selecting the object, copy and pasting, then using the normal tool, but i have little success. Is there no way to globally reverse all the faces, or the vertice order?

Thanks

Steve

[Thomas]

the "backface" is only a display option. When you export, you are always exporting all your polygons. Then, take a look in your software where you don't have the backfaces displayed, if you have an option to see them.

Eventually, apply a thinckness to avoid this problem, but it will double the number of polygons...

[Piem]

back faces are alway exported ..they are not object it's only a display setting.
or ,It's a feature you only have to enable in your render..
For hexagon it's down the desk..an icon on the right

[Lister]

Originally Posted by arteria

I have a Helment for a knight i am working on, and i need the inside of the helment to show faces, so it doesnt look transparent when the model is wearing the helment.

Ah, yes, Professional terminology, the bane of the n00b.. ;-)

I don't have the answer, but I can rephrase your question for you so that the others know what you're talking about (and besides, I'm curious, too):

Is there a way in Hexagon to convert polygons to doublesided?

Now as I said, I haven't gotten far enough into Hexagon to know whether it can or not, but I can tell you that there are other programs out there that will do it for you. One of the slickest progs out there that will do this for you is "Exploration3D" (although I think it's now called "Deep Exploration").
The best use for doublesided polygons is for clothes. A helmet made from them will greatly improve its aesthetics, but remember that you are working with a single plane, and the helmet may still look weird from certain edge-on views because it has no thickness. A better way, albeit more work, is to extrude the helmet surface a tad and rescale that surface slightly to give the helmet a uniform thickness. Then just flip the UVs on that surface and you'll pretty much have what you're looking for.

[LoneGunman]

Double sided polys are render effect, it is achieved by ignoring poygon normals, no need for modeling app to "convert" anything

[Lister]

Originally Posted by LoneGunman

Double sided polys are render effect, it is achieved by ignoring poygon normals, no need for modeling app to "convert" anything

Nope. A double sided polygon is two polygons occupying the same plane space but with opposite normals.

[Piem]

Originally Posted by Lister

Nope. A double sided polygon is two polygons occupying the same plane space but with opposite normals.

O_O

basically ; maybe are you right ,I am not a fundamentalist neither a mathematician.
but when you make : click click click ..you have drawn a tri sided polygon , ONE polygon which has already a back face

[LoneGunman]

Originally Posted by Lister

Nope. A double sided polygon is two polygons occupying the same plane space but with opposite normals.

Sounds to me, whichever rendering engine needs this, like terrible waste of space (doubles amount of polygons). Even OpenGL can do this on the fly (apply different texture on different sides).

[tonytrout]

I get a little lost here?

When I bring object into rendering programme C5 here it doesnt matter whether the object has thickness or not, you can still see both sides of the face. I show in picture below

1 and 3 are simple curved single polygon grids
2 and 4 have thickness ie they now have dual polygon grids to make the walls

1 and 2 have been shaded with a simple wood procedural
3 and 4 have been UV mapped and photo applied

In each case the two sides are visible. Maybe I not get what you are about?
cheers tony

[Lister]

Wow! This seems to be confusing everybody!
Okay, doublesided polygons were born in the early days of 3D when renderers didn't have the capability of rendering backfaces. Yes, gang, there really was a time when microprocessors ran at a blistering 8MHz and a meg of ram was massive. ;-)
Today they have very limited use. As Gunman notes, OpenGL (and others) can render backfaces on the fly.
Some preview renderers still don't though. A classic example is Poser, and I have included 2 images to show everyone what I'm talking about.
I made 2 identical wavy planes (like a curtain), except that the top one uses doublesided polygons, and loaded them into Poser. The 1st pic shows the two curtains from the front and you can see they are identical. The second pic shows them from the back, and you can see the problem with Poser's preview renderer. Poser does, however, render backfaces in full render.
So as virtually pointless as they may be today, I just figured I'd illustrate that they do exist for whatever purpose that someone like Arteria might want them. ;-)

[LoneGunman]

Oh, I actually remember those times well, my first 2 computers were Apple IIc and Sinclair's ZX81, I'm not that young

I have Poser4, and indeed, it has problems rendering polygons with inverted normals. They are invisible in preview mode, you are right about that

Older game engines used to behave the same way...

[arteria]

Thanks for all the help.. Basically i need double sided faces on my object because its to be used in a game, and at the moment, the helment i have modelled has no backfaces, therefore when the character wears it, the inside just renders black in the game engine, or transparent effect

[tonytrout]

You can add another layer of polygons with the thickness tool

[arteria]

Thankyou, ill give that a go

[tonytrout]

You might also need to maintain the sharp edges to your helmet using the crease option under the smooth tool, as when you add thicckness and subdivide it will round off your edges.

[Lister]

Arteria, just to keep things pointed in your direction<g>, Tonytrout gives what would probably be your best solution. Not only does adding thickness give you your backfaces, it also gives your helmet "substance".
Would that solve your problem?

Originally Posted by LoneGunman

Oh, I actually remember those times well, my first 2 computers were Apple IIc and Sinclair's ZX81, I'm not that young

Ahhh, those were the days, my graying compadre... ;-)
My first comp was a TRS-80 Model 4. Timex Corp bought Sinclair at some point and reintroduced the ZX81 as "Timex-Sinclair 1000" (copyright 1982!). I have one of them, still in the original box. Funny, both the TRS-80 and the Sinclair used the same CPU, Zilog's Z80. And to undercut my previous post even more, my TRS-80 was fully loaded with the max 64K of ram and clocked at 4MHz! ;-)