17 Replies Latest reply on Sep 24, 2008 1:12 AM by craig sinclair

Zebra Stripes

Alessandro Frattini Sep 15, 2008 5:53 AM

Hi,
I attached the file and tree images.
SW and the same analysis in Rhino.
In Rhino is OK and in SW you noticed strange artifacts.

Cubic mapping on a cube.
This is a result that goes against the laws of geometry and good sense.

Can someone explain me why ?

Thanks,
Alessandro

Part112.zip 2.8 KB
cubo.jpg 6.8 KB
sw3.jpg 7.2 KB
rh.jpg 5.1 KB

Zebra Stripes

Alessandro Frattini Sep 16, 2008 5:54 AM (in response to Alessandro Frattini)

Hi,
sorry, but I'd love to get a response from someone in this forum.
On Italian SolidWorks forum, every day we are attacked by different CAD, once SolidEdge, once Pro-E, one from Inventor and so forth every day.
I use SolidWorks from '97, but certain features like this do not I ever needed and then head.
Today is the turn of Think3 and Rhino.
I would like to contradict those of Think3 and Rhino with technical answers that can silence these evil languages.

Mark Biasotti, you might respond with some words of this difference and help defend SolidWorks.

Thank you,
Alessandro
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  1-9C36HC Sep 17, 2008 12:02 AM (in response to Alessandro Frattini)
  
  Alessandro,
  
  Not meaning to defend, but just caught up with this thread tonight and would have reponded to it anyway :-) . The difference you're seeing between the rhino and SW zebras are due to the fact that the coordinate systems are different between our two programs. If you simply rotate your surface using the move/copy surface function, you can rotate the surface body on it's X axis -90 degrees. In Rhino, Z is up while in SW Y is up with Z pointing outward. The cube and sphere maps in our zebra are not rotate-able so the poles of the zebra map are alway Y and -Y. If you really care about this, there is a workaround - you can load you're own RV zebra map scene and essentially do the same thing (that is if you have RV graphics capability) except you get more control because you control the RV Spherical image - you can go to SW Labs post click here to see how to create your own RV environment and more specifically controllable zebra environment. The additional benefit is that it is faster and pervasive (can use it while you model.)
  
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    craig sinclair Sep 17, 2008 5:57 AM (in response to 1-9C36HC)
    
    Mark,
    Why is the Coordinate system different? Shouldn't Z always be up? I use Solidworks, Rhino and CAM programs (mainly edgecam) and I find this to be most frustrating. I do a lot of CNC programing and i have never seen a CNC mill were the Y is up and down and Z is forward and back. Would it be possible in future Solidworks releases to be able to change the Global origin? Whether it prompts you to set the global origin during an instal or when begining a part i think this would be of value.
    
    I have made a template basically were i changed my views and renamed my top, front and right planes to get it how i want but this makes normal to useless.
    
    Thanks for your time, Craig
    
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      Philippe Keirse Sep 17, 2008 7:00 AM (in response to craig sinclair)
      
      Graig,
      I'm totally agree with you.
      It's frustrating, especially for parts for CNC milling.
      We always lose time to turn the part in the correct position.
      
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      1-9C36HC Sep 17, 2008 5:17 PM (in response to craig sinclair)
      
      Craig,
      
      Because Rhino wasn't around when we released SW'95 and we took our que from ProE.
      
      All is not lost though - If you regularly work between Rhino and SW, you can create a customized template "slddot" that sets up your new part with Z pointing up.
      
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        Paul McGarr Sep 18, 2008 11:40 PM (in response to 1-9C36HC)
        
        Mark,
        
        Please explain how to swap config so Z is up. Every time I tried this in the past something wouldn't work right.
        
        I come from a CNC background, and I also find y-up confusing. I'd love to change the orientation if it doesn't screw anythig up.
        
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        Chris Littleford Sep 23, 2008 3:54 PM (in response to Paul McGarr)
        
        Paul McGarr wrote:
        
        Please explain how to swap config so Z is up. Every time I tried this in the past something wouldn't work right.
        
        Paul,
        Start a new part and rename your planes to something that has meaning for you. (XY Plane, XZ Plane, YZ Plane) As a machinist you don't care which side is the front, you only care where your origin is and which way you axis go.
        
        Next, click the bottom view from the Standard Views toolbar. Hit the spacebar to bring up the Orientation box. Single Click *Front (the view should not change) and then click the Update Standard Views (the middle button) of the Orientation box. If you now view an isometric view you will see the Z pointing toward the top of the screen and Y points into the screen.
        
        To save this as your template go to File/Save As move to the templates directory and rename the file. In the Save As Type box select Part Templates (*.prtdot).
        
        You can use this method to create any orientation you like. I hope that helps.
        
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      Mark Matthews Sep 18, 2008 12:48 PM (in response to craig sinclair)
      
      Craig,
      
      This has always bugged me too, but the xyz thing is rooted in how these programs were originally used. MCAD programs like Pro-E and SW started by catering to users based in the 2-D drafting world. A sheet of paper has x and y coordinates with y being the vertical axis. When this paradigm was translated to 3-D, the z axis became the distance behind the screen. When Alias started by being a television graphics engine (no mechanical background, hence no drafting legacy) they always worked in a 3-D space and took xyz as used in the rest of the world. Other animation packages followed suit (Rhino's base engine was based on the Alias kernel from what I've heard). In machining, the table of the mill was always considered x and y, with z being manipulated by raising the table or the chuck.
      
      Of course, I could be completely wrong.
      
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        John Summers Sep 18, 2008 9:07 PM (in response to Mark Matthews)
        
        Cad programs aren't the only ones with the coordinate issues. We regularly use Solidworks and previously, Solid Edge to produce models to translate into CFD software. Depending upon which CFD software we were exporting to, we had to be aware which coordinate system to set up the CAD model to as the CFD softwares vary also. Very confusing at times!
        
        It would be nice to have the ability to control the coordinate origin and direction within the model after it was produced. Our work-around is to reposition it in the assembly mode.
        
        (Apologize for the continued hijack- maybe this could be continued on another topic?)
        
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      Tom Nicholson Sep 23, 2008 4:04 PM (in response to craig sinclair)
      
      craig sinclair wrote:
      
      I do a lot of CNC programing and i have never seen a CNC mill were the Y is up and down and Z is forward and back.
      
      You've never used a vertical mill?
      
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        Paul McGarr Sep 23, 2008 4:16 PM (in response to Tom Nicholson)
        
        Tom, if your going to be a wise guy, you should make sure to get it right. I believe you mean horizontal mill.
        
        There are all types of machines, but in practice, you walk into most shops and their mills are X (left right) Y (front back) and Z (up down). Typically when I set up a horizontal mill, top is still perpendicular to Z.
        
        I think I am going to make the change to our templates here. Does anybody see a negative to doing so?
        
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    Alessandro Frattini Sep 17, 2008 7:45 AM (in response to 1-9C36HC)
    
    Mark Biasotti wrote:
    
    ....If you really care about this, there is a workaround - you can load you're own RV zebra map scene and essentially.......
    
    Hi Mark,
    thanks for your time.
    I followed your suggestions, creating a new map scene from SW Labs, but I wasn't able to get the result as with Rhino and Think3.
    How does the map scene has affect to the zebra stripes ?
    If you mean to create a new texture to be applied to the surface / body, the texture is not prepared ever as the analysis tool.
    I apologize if you lose any more time, but understand how the map scene affects to zebra stripes, I can create this map scene environment and then put into SolidWors Italian forum and close this diatribe.
    
    Alessandro
    
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      1-9C36HC Sep 17, 2008 5:25 PM (in response to Alessandro Frattini)
      
      Allessandro,
      
      The customer RV environment does not affect the Zebra stripe display function in any way, but rather is an alternative to you. You can see this affect by using the customized RV zebra stripe scene and turning your part to "chrome" material (something I forgot to mention in original reply) therefore you have a RV scene/environment reflecting white stripes onto your part.
      
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        Alessandro Frattini Sep 18, 2008 5:37 AM (in response to 1-9C36HC)
        
        Thanks Mark,
        now it's entirely clear.
        
        Alessandro
        
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Zebra Stripes

1-8MMYCK Sep 18, 2008 2:25 AM (in response to Alessandro Frattini)

it seems like the sides the of cube which solidworks uses for zebra stripes is located at infinity. (when you get normal to the surface,zibra stripes of flat surfaces converge at a point)
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Zebra Stripes

Tom Nicholson Sep 23, 2008 4:26 PM (in response to Alessandro Frattini)

ahh dammit.. your right.. guy walked in and started talking about one of the verticals in the shop when I was typing this.. lol
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  craig sinclair Sep 24, 2008 1:12 AM (in response to Tom Nicholson)
  
  Sorry guys this thread kind of got a little hijacked. I've started a new one here.
  
  link
  
  Paul it has a template for you to try.
  
  Yes Tom i have used vertical mills
  
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