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How do I get smooth curves?
Posted: 12 November 2012 12:11 PM   [ Ignore ]
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Hello,

I modeled the object in the attached picture. As you can see, there are some jaggies along the curved edges.
What I did is:

1-create a cube with tess 48
2-Create a an arc with 256 points
3-Bend the cube along the arc
4- Use smoothing level 1

I end up with 127898 tris but still a lot of jaggies.

How could I do this so that I get smooth curves everywhere?

Thanks!

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Posted: 12 November 2012 08:35 PM   [ Ignore ]   [ # 1 ]
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How did you end up with tris??

No matter…there’s an easier way that will give you better results with more control: Use the “sweep line” tool.

Create the arc you want adjusting the number of points in the line to whatever pleases you. Your example uses 256 which is quite dense.

Also using a line, create the shape you want the arc’s body to assume. In your case, starting with a cube I would assume you want a “square” cross-sectional shape. In this case instead of making a square with a line tool you can use the “square” or “rectangle” maker which is also found in the “Lines” tab.

Place the square at one end of the shape, select the “sweep line” tool under the “Surface Modeling” tab, and then click on your arc.

The square will sweep the line using as many segments as you created the line with (in your case, that would be 256 segments).

There’s quite a few ways of fiddling with the controls, lines and cross-sectional shapes (you can use more than one and they don’t all have to be the same size or shape) and playing with these variables can be quite rewarding.

But even the simple 1-2-3 steps I just gave will probably give you far superior and more satisfying results than trying to beat a cube into submission.  grin

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Posted: 12 November 2012 08:39 PM   [ Ignore ]   [ # 2 ]
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Somebody please delete this…

Somehow I managed to quote and re-post my previous message.  rolleyes

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Posted: 13 November 2012 02:54 AM   [ Ignore ]   [ # 3 ]
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Looks like kzamor needs a bit of twist in the swept profile. How could you do that with sweep line ?

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Posted: 13 November 2012 03:15 AM   [ Ignore ]   [ # 4 ]
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ausair - 13 November 2012 02:54 AM

Looks like kzamor needs a bit of twist in the swept profile. How could you do that with sweep line ?

Actually I took the twisting as an unintended artifact from bending, even though it doesn’t look at all unattractive.

However, if he does want the twist, the sweep control has a “taper” and a “twist” setting that can be played with.

Here’s the same 2 objectx as obove with an arbitrary “400” as a twist factor. Leaves a bit to be desired for closed loops but you can get pretty complex with open lines such as arcs.

 

 

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Posted: 13 November 2012 03:28 AM   [ Ignore ]   [ # 5 ]
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Never noticed the twist option, thats pretty cool.

I created it with circle (couple of edges deleted) and rectangle (profile) as per afreaginname post with a twist of 20.

Your don’t really have a lot of control of the twist.

It would be nice if you could sweep multiple profiles along the circle so you have more control of how and where you want it to twist. Maybe Hex 3 ?......Dream on.

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Posted: 13 November 2012 04:04 AM   [ Ignore ]   [ # 6 ]
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ausair - 13 November 2012 03:28 AM

It would be nice if you could sweep multiple profiles along the circle so you have more control of how and where you want it to twist

GAAK!!! In my first post I actually stated that could be done - I was wrong…I just tried it, and hex just created a separate solid for each profile all laid on top of each other. Even the “tool tip” says “a section and a profile” so there’s no way around it; one profile is all we get.

Maybe Hex 3 ?......Dream on.

I hear DAZ is going to bundle it “real soon now” with the Brooklyn Bridge as a special offer to hexagon users…  smile

 

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Posted: 13 November 2012 05:02 AM   [ Ignore ]   [ # 7 ]
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I guess the other way you could create the specific shape with the twist you want is via gordon surface. With that tool you could have multiple rectangle profiles + 4 semi circular curves to join them together (1 curve on each corner).

or

model using low poly box modelling approach and use 2 levels of sub’d (smoothing) possibly creasing the edges.

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Posted: 13 November 2012 10:12 AM   [ Ignore ]   [ # 8 ]
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Hi Guys, thanks for all the replies!

Yes, the twisting is part of the design like in afreaginname’s post. But I really want smooth edges, just like if I sculpted it in wood and then sanded it down to a 1000 grit. I don’t care if it takes boatloads of memory or takes ages to render, I just want it to look smooth!

Even at 263000 polys, it’s still jagged at some places. I must be doing something wrong. Any ideas?

At which steps should I apply the smoothing?

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Posted: 13 November 2012 11:52 AM   [ Ignore ]   [ # 9 ]
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Instead of a line along the outer edges, suggest you try chamfer along that edge

Also try using more & smaller boxes along the extrusion length….if using a line as a guide path, use more points along the line

Also you can do some smoothing in post by rendering larger than needed (hi res render), add a touch of blur, the reduce image to size needed….and assess from its intended use….for example as a web page display it will likely look pixelated, but a hi res render to print @ 300 ppi/dpi (not going to get into that discussion) viewed at normal distance should look great.

Of course there are several smoothing methods/choices; some do better than others (i.e. don’t just click on smoothing; look at tool box choices)

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Posted: 13 November 2012 02:42 PM   [ Ignore ]   [ # 10 ]
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You mean something like this?

Used a rectangle with chamfered corners as a profile, a circle with 36 points as the sweep path.  Smoothed level 1 gives 4032 polys.

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TWIST.JPG
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Posted: 13 November 2012 03:06 PM   [ Ignore ]   [ # 11 ]
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In the end, I want something with the level of smoothness you see in the attached images. You see, no jaggies at the edges at all.
Right Now, To get something close to this in smoothness, I have to render at 10000 X 10000 which isn’t always possible when there is a lot of objects on screen, not enough RAM.

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RASMUSSEN_002.jpgMerete_Rasmussen_Yellow_Twisted_Form,_Contemporary_Applied_Arts,_London_.jpg
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Posted: 13 November 2012 03:19 PM   [ Ignore ]   [ # 12 ]
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I think for those shapes you would want to model a low poly cage and apply 2 or more levels of smoothing (sub’d).

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Posted: 13 November 2012 03:40 PM   [ Ignore ]   [ # 13 ]
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Please forgive my ignorance, but what is a low poly cage?

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Posted: 13 November 2012 04:09 PM   [ Ignore ]   [ # 14 ]
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OH NOOOOO!!!!!

Is THIS what you’re calling “jaggies”??? The ONLY way you’ll get rid of them is to do a full rendering with antialiasing!

You have to understand the medium you’re playing with here. Lines and curves are built up of discrete sections that are exactly one pixel wide and high on your screen. On a quick render like you have here, the pixel is lit if more than half of the calculated point overlays that pixel and not lit if less than half. An LCD screen (say) CAN NOT SHOW half a pixel on 2 adjacent pixels. Drawing a straight computer line top to bottom on a computer screen when the top pixel is one pixel to the right of the colomn that the bottom pixel is on results in a vertical line from the top pixel straight down to the middle of the screen, and then it jumps over one pixel and draws the rest of the line straight down to the bottom pixel. This gives you a “jag” in the center of the line.

Antialiasing fools the eye by adding shading to these pixels according to how much of the pixel would be covered if it were a true “line”. The mathematical definition of a “line” is an infinite number of points lying between 2 endponts, but computer monitors don’t have an infinite number of points.

Here’s a thought experiment for you: Take a bunch of square pieces of paper. Lay 2 of them out as endpoints of a line. Now take others and connect them so that there’s a continuous path of squares between the starting square and the ending square with the following restriction: The squares can only touch at corners or along full edges. They can’t be overlaid in anyway.

This is how computer monitors draw lines on screens.

PS: Your image is monochrome, and this greatly exacerbates the “jaggie” effect. Adding colors to both object and background areas aids the antialiasing engine in creating the illusion of smoothness, and this is why your other samples look smoother than your original image.

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Posted: 13 November 2012 04:14 PM   [ Ignore ]   [ # 15 ]
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kzamor - 13 November 2012 03:40 PM

Please forgive my ignorance, but what is a low poly cage?

If you have, say a square mesh that has a grid of 1000 x 1000 quads (which are 4-sided POLYgons), you end up with a mesh having a million faces. This is EXTREMELY hi density and difficult to work with. By creating the same mesh using only 10 x 10 quads, you end up with the same mesh but a lower poly count of 100 faces.

Cages, solids, planes…all the same principle.

 

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