[project1dev] Re: Scale
- From: Alan Wolfe <alan.wolfe@xxxxxxxxx>
- To: project1dev@xxxxxxxxxxxxx
- Date: Sat, 27 Jun 2009 22:06:33 -0700
yeah thats totally possible.
In line rider btw we had a bezier curve tool and basically the bezier curves
were aproximated with ALOT of really small line segments.
what i did after i created all the small line segments is loop through and
look at where the angle difference between 2 neighboring lines, divided by
their combined length was under a certain number.
If it was under that number, then the vert could be removed.
What that resulted in (if you ever play the game you can see) is that there
are more lines where it's more curvy and less lines where it's more
straight.
it's a type of LODing i guess hehe.
but yeah, if you wanted to ADD more verts when you get close, your best bet
might be to aproximate the model with shapes (curves, spheres, boxes, etc)
and so if there was a sphere shape that needed more verts you could add more
verts on the sphere.
but!
a lot of magic can happen with detail textures and bump mapping where you
can get what looks like really good detail without needing to add more
verts.
for instance, a lot of games, when you get too close to the terrain, instead
of the terrain looking really stretched and washed out, they will render
another texture on top and blend it in that looks like even more detail.
Distant terrain doesnt get that treatment.
So yeah, you can deffinately add in more detail too! but of course adding
detail you are always guessing and theres the chance of getting it really
wrong, especially the more you zoom in!
On Sat, Jun 27, 2009 at 10:01 PM, Chris Riccobono <crysalim@xxxxxxxxx>wrote:
> Yeah, the texture optimization you mentioned makes a lot of sense, but
> the vertex one is where it gets really amazing. Being able to notice
> in code when you can take out edges is really cool.. and yeah, all of
> those effects like putting fog in the distance so you can't notice
> those low poly models, I remember the n64 having to do that so many
> times :P
>
> I wonder if it possible to scale a model up the closer it is? Like
> when you get too close to an object that doesn't have enough verts to
> fill itself in short range?
>
> On Sat, Jun 27, 2009 at 9:57 PM, Alan Wolfe<alan.wolfe@xxxxxxxxx> wrote:
> > Techniques like this are also used at runtime and are called "LODing"
> where
> > LOD stands for "level of detail".
> >
> > For instance in games when objects are far away they sometimes use lower
> > poly models since its really hard to tell the difference.
> >
> > Or also a lot of times in outdoor scenes in video games where there's a
> lot
> > of mountains and ground you can see at once, distance land uses less
> verts
> > since you can't tell anyhow.
> >
> > As you run around you might notice little bumps appear and disapear and
> > that's called "popping" and is something every LOD technique can
> potentially
> > have a problem with, but there are also techniques for minimizing popping
> > such as instead of removing a vert in one frame, you move the vert over
> time
> > to where it's in line with how the model would look without the vert,
> then
> > you remove the vert so it has a smooth transition which is harder to see
> > than a visible pop.
> >
> > man there is so much crap that goes into makin video games! this is just
> > the tip of the ice berg of one topic of hundreds :P
> >
> > On Sat, Jun 27, 2009 at 9:52 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx>
> wrote:
> >>
> >> there's algorithms for things like this.
> >>
> >> for textures you can calculate at various distances how many texture
> >> pixels there are per screen pixels (also taking into account the
> object's
> >> scale) and try to make it 1 to 1.
> >>
> >> For instance if something has a super high resolution texture or is
> scaled
> >> way down, you might have 8 texture pixels per screen pixel which is a
> lot.
> >> You could then make the texture 1/8th as large and have it so 1 texture
> >> pixel equals 1 on screen pixel.
> >>
> >> That's the ideal most of the time.
> >>
> >> similarly for models, you can take a look at each vertex and if you
> remove
> >> the vertex see how many pixels on screen would "pop" and anything which
> was
> >> within the reasonable tolerance, it would get rid of, but keep from
> removing
> >> vertices that make a huge impact.
> >>
> >> Like for instance if you had a cone shaped nose for a character you
> >> wouldn't remove the tip of the nose cause that would make the nose go
> flat
> >> which is really noticeable, but you might remove some of the vertices on
> the
> >> base of the nose since doing that is going to make it less round, but
> that
> >> doesnt really affect how the model looks.
> >>
> >> these are just 2 ways but theres all sorts of algorithms to do this
> stuff
> >>
> >> On Sat, Jun 27, 2009 at 9:47 PM, Chris Riccobono <crysalim@xxxxxxxxx>
> >> wrote:
> >>>
> >>> Wow, that really is impressive. That gives artists and builders so
> >>> much more freedom it's crazy. I don't even know how one would go
> >>> about creating that system!
> >>>
> >>> On Sat, Jun 27, 2009 at 9:42 PM, Alan Wolfe<alan.wolfe@xxxxxxxxx>
> wrote:
> >>> > Oh and something really interesting to note!
> >>> >
> >>> > The geniouses at ID software (carmack etc) have their current engine
> >>> > working
> >>> > where artists submit huge high resolution textures and way high
> >>> > polycount
> >>> > models, and the engine scales each down to only what is needed and
> >>> > automatically gets rid of the waste.
> >>> >
> >>> > it's a neat system, but ID software is like the best of the best so
> >>> > it's no
> >>> > surprise :P
> >>> >
> >>> > On Sat, Jun 27, 2009 at 9:32 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx>
> >>> > wrote:
> >>> >>
> >>> >> Well the scaling issues should all but disapear because the artists
> >>> >> are
> >>> >> going to make models to scale and building won't require making
> things
> >>> >> the
> >>> >> right size for the most part. This is important too because an
> >>> >> artist
> >>> >> makes a model to be a specific size. If a builder make it bigger
> than
> >>> >> that,
> >>> >> it's going to look bad like you saw with the stretched textures.
> >>> >>
> >>> >> The solution to the problem you hit is just to have the artists make
> >>> >> objects the right size and have the builders not have to worry about
> >>> >> it.
> >>> >>
> >>> >> the idea of being able to place a bunch of models down in specific
> >>> >> intervals is a good idea, its probably something we'll need a lot.
> >>> >> This can
> >>> >> be done via some script magic currently but i'll put it on the list
> as
> >>> >> a
> >>> >> wish item for later (:
> >>> >>
> >>> >> something you might like, is if you type "clone" in the console when
> >>> >> you
> >>> >> have something selected, it will clone your selection so that when
> you
> >>> >> click, it will place an object rotated and scaled the exact same
> place
> >>> >> where
> >>> >> you click. that should help with this point you bring up too.
> >>> >>
> >>> >> In general we want to only use as many verts and texture resolution
> as
> >>> >> we
> >>> >> need.
> >>> >>
> >>> >> It's true that if we give a higher res texture to an object and
> extra
> >>> >> verts then we can scale it up and it will still look good, but with
> >>> >> the
> >>> >> artists making objects of the right size for the game, we won't ever
> >>> >> be
> >>> >> scaling things past where they should be so i think the artists
> should
> >>> >> keep
> >>> >> on doin like they have, just use the lowest res texture needed to
> make
> >>> >> an
> >>> >> object look good at the scale they want it.
> >>> >>
> >>> >> make sense?
> >>> >>
> >>> >> On Sat, Jun 27, 2009 at 9:17 PM, Chris Riccobono <
> crysalim@xxxxxxxxx>
> >>> >> wrote:
> >>> >>>
> >>> >>> Not to keep begging for more editor features....
> >>> >>>
> >>> >>> But if we have setscale combined with being able to see exact
> >>> >>> dimensions of a model when you click on it, then we could have
> >>> >>> setsize
> >>> >>> and keep placing models to that exact dimension set. And then
> >>> >>> combined with the snapto command, we could actually keep placing
> >>> >>> models every set amount of space, and they would be exactly
> aligned.
> >>> >>>
> >>> >>> I don't know if this makes full sense but it did when I was typing
> it
> >>> >>> :x
> >>> >>>
> >>> >>> On Sat, Jun 27, 2009 at 9:15 PM, Chris Riccobono<
> crysalim@xxxxxxxxx>
> >>> >>> wrote:
> >>> >>> > When I was building I found it easier when a model had a good,
> high
> >>> >>> > res texture. They can't be too big cuz of cost, of course, but
> if
> >>> >>> > the
> >>> >>> > texture is unrepeating and pretty, you can almost scale the model
> >>> >>> > any
> >>> >>> > way you want and not have to worry.
> >>> >>> >
> >>> >>> > When making floors, walls, and ceilings, it seems better to have
> >>> >>> > lower
> >>> >>> > res and lower size models. This helps when tiling and aligning
> >>> >>> > things. For example, the first version of the voidmap had some
> >>> >>> > issues
> >>> >>> > because the main asteroid was very large and oddly shaped. I had
> >>> >>> > to
> >>> >>> > almost scale it to a pancake on the Z axis because of that, and
> >>> >>> > even
> >>> >>> > then there were still problems with being able to walk under and
> >>> >>> > around things placed on it.
> >>> >>> >
> >>> >>> > Oddly shaped models are very pretty as decoration though, like
> the
> >>> >>> > fortune teller tent props, the rock piles in cavemap, and the new
> >>> >>> > trees in voidmap.
> >>> >>> >
> >>> >>> > Hey Alan, maybe we can get around the iffyness of scaling in the
> >>> >>> > editor by being able to set a value of default scale in the
> >>> >>> > console.
> >>> >>> > Maybe something like "setscale 0.5 0.5 0.5", so then everything
> you
> >>> >>> > place will already have a scale of that value.
> >>> >>> >
> >>> >>> >
> >>> >>> >
> >>> >>> > On Sat, Jun 27, 2009 at 10:46 AM, Alan Wolfe<
> alan.wolfe@xxxxxxxxx>
> >>> >>> > wrote:
> >>> >>> >> Yeah, just to re-iterate, scaling in the editor is just like
> what
> >>> >>> >> happens in
> >>> >>> >> real life if you stretch an object.
> >>> >>> >>
> >>> >>> >> the texture stretches too and will look distorted if you stretch
> >>> >>> >> it
> >>> >>> >> too
> >>> >>> >> much, or stretch it too far on one axis vs the others
> >>> >>> >>
> >>> >>> >> the idea is that when we make models we want to make it so 10
> >>> >>> >> units =
> >>> >>> >> 1
> >>> >>> >> meter so that when a builder places an object in the level that
> >>> >>> >> they
> >>> >>> >> dont
> >>> >>> >> have to scale it, since the artist has an idea of how big the
> >>> >>> >> object
> >>> >>> >> should
> >>> >>> >> be in the world, and scaling takes extra time when building.
> >>> >>> >>
> >>> >>> >> thats the ideal, but of course it may take us quite a few
> >>> >>> >> iterations
> >>> >>> >> before
> >>> >>> >> we are all on the same page about how to make that happen (:
> >>> >>> >>
> >>> >>> >> On Sat, Jun 27, 2009 at 9:43 AM, Nick Klotz
> >>> >>> >> <roracsenshi@xxxxxxxxx>
> >>> >>> >> wrote:
> >>> >>> >>>
> >>> >>> >>> Textures get stretched and compressed at the same ratio you
> >>> >>> >>> scale.
> >>> >>> >>>
> >>> >>> >>>
> >>> >>> >>> On Sat, Jun 27, 2009 at 9:45 AM, katie cook <ktmcook@xxxxxxxxx
> >
> >>> >>> >>> wrote:
> >>> >>> >>>>
> >>> >>> >>>> Hey Guys,
> >>> >>> >>>>
> >>> >>> >>>> When you scale a model in the level editor, does it scale the
> >>> >>> >>>> textures
> >>> >>> >>>> proportionately? OR does it stretch them as you scale?
> >>> >>> >>>>
> >>> >>> >>>
> >>> >>> >>
> >>> >>> >>
> >>> >>> >
> >>> >>>
> >>> >>
> >>> >
> >>> >
> >>>
> >>
> >
> >
>
>
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