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Subject: 
Re: Lpub find edges
Newsgroups: 
lugnet.cad, lugnet.cad.dev
Date: 
Sat, 3 Apr 2004 15:47:12 GMT
Viewed: 
974 times
  
In lugnet.cad, Tim Courtney wrote:
   In lugnet.cad, Ahui Herrera wrote:
   In lugnet.cad, Paulo Caparica Junior wrote:
   I am not getting lpub to generate nice edges. At this picture the windscreen is a blob with edges only around it:

http://www.brickshelf.com/gallery/caparica/Town/Truck/ib200p16a006ci.jpg

And the wheel hubs have a series of ugly black dots:

http://www.brickshelf.com/gallery/caparica/Town/Truck/ib200p16a007ci.jpg

Does anyone know the right parameters to get well defined edges?

Paulo

Paulo, the “right parameters” depends on what size resolution you are creating your BIs.

I use a 1600x1200 image resolution for me BIs and then shrink them to whatever I need.

Based on a 1600x1200 res, I have found that these parameters work good.

2, //depth difference required for line

0.35, //angle difference required for line

0.2, //color difference required for line

1.2, // 2.0 default line width

You should note that the value for the line width is relative to the resolution of the image, not relative to the size of the object being rendered. So, if you render a brick that takes up almost all of the space in your image, your line will appear thin relative to the brick, where if you have a rendering of a brick that is very far from the camera, the line will appear thick relative to the brick.

This is so very true, and troublesome.

POV-Ray does not support the concept of a line in 3D space, so L3P cannot directly translate LDraw lines to POV-Ray entities.

Lars, at one point we talked about the possibility of having L3P use cylinders as edge lines on parts. Was there ever any effort made on this?

I guess LPub could try to calculate good values for line width..... given a camera distance and an image resolution, LPub could render a 2x4 brick and measure the bounding box. The dimensions of the box could be used to figure out how thick the line should be. I have no idea how I would calculate the other parameters.

Feedback?

  
-Tim

Kevin



Message has 2 Replies:
  Re: Lpub find edges
 
(...) Cylinders would not resolve every edge lines, at curved surfaces that would be a problem. There are comercial renderes that do that line and flat surface stuff. They are used a lot to blend 3D CG with cell animation drawings. I have not (...) (20 years ago, 3-Apr-04, to lugnet.cad, lugnet.cad.dev, FTX)
  Re: Lpub find edges
 
(...) Well, I did some tests walking the tree and printing out all line type 2 as cylinders, but I didn't think it looked to well. Mostly because at some edges you only see 1/4 of the cylinder, and at other edges you see 3/4 of the cylinder. L3P (...) (20 years ago, 12-Apr-04, to lugnet.cad, lugnet.cad.dev)

Message is in Reply To:
  Re: Lpub find edges
 
(...) You should note that the value for the line width is relative to the resolution of the image, not relative to the size of the object being rendered. So, if you render a brick that takes up almost all of the space in your image, your line will (...) (20 years ago, 3-Apr-04, to lugnet.cad, FTX)

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