AutoCAD

Discussion in 'General Chat' started by MO!, Jun 24, 2003.

  1. MO!

    MO! MOnkey`ead!

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    Q) Which one of these best describes a "local coordinate system"?

    a) A pair of coordinates which define the lower left and upper right corners of the drawing boundary?

    b)A series oof coordinate points stored as variables for later use in the drawing?

    c) A coordinate system whose origin is located anywhere in 3 Dimensional space?


    d) A means of logically grouping drawing entities so that visibility can be controlled?

    ---------------------------------

    a) sounds like it's just decribing the limits. And to me b)c)and d) sound all like possible answers :confused:
     
    Last edited by a moderator: Jun 24, 2003
    MO!, Jun 24, 2003
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  2. MO!

    MO! MOnkey`ead!

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    System variables.

    a) automate the use of commands?

    b)customise menus and pattens?

    c) select suitable drawing aids?

    d) specify the hardware configuration?

    AhhHhHhHhHhhHhhH!!!!

    all of them?
     
    MO!, Jun 24, 2003
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  3. MO!

    julian2002 Muper Soderator

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    not sure about autocad but c is probably closest to what i understand as a local co-ordinate system from my work with 3d cg.

    a co-ordinate system consists of an origin (nominally 0,0,0 but it could be anything) and 2 vectors describing 2 directions, up and at (or y and z ) right or x can be derived from the up and at.
    usually up is up the screen and at is into the screen but again this can vary.

    another way of describing it would be a frame of reference.

    in my work i have to deal with world co-ordinates, camera co-ordinates and individual model co-ordinates. i would describe a local co-ordinate system at the model level co-ordinate system with a transformation (rotation and translation or movement) turning each models local co-ordinates into world co-ordinates. finaly a camera transform is applied before rendering.

    any help?
    cheers

    julian
     
    julian2002, Jun 24, 2003
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  4. MO!

    julian2002 Muper Soderator

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    system variables probably control things like whether you are using metric or imperial units, what colour the backdrop is etc...
    but then again i'm not an expert on autocad.
    cheers


    julian
     
    julian2002, Jun 24, 2003
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  5. MO!

    Robert Edgar

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    For the local co-ordinate system
    I probably would go with answer "c"

    This taken off a web page

    Under the AutoCAD for Windows R12 environment, an AutoLISP program updates the position/orientation of the excavator and its trenching operations at real-time. Every 3-D perspective view will be based upon a fixed world coordinate system (global coordinate system) that is set up by the SPS. However, since the trenching operation takes place within one plane and movements of different links of the excavator can be depicted relative to the excavator's base, it is convenient to implement the trenching operations under a local coordinate system (excavator coordinate system), with its origin at the center of the excavator's swing base. Therefore, the operator is able to see the 3-D field with the excavator operations, the trench under excavation, and other objects such as pipes under the SPS coordinate schemes. At the same time, he/she can also view the digging motion under the plan view and side view. It is believed that the above combination technique provides an excellent interface to enable the operator to manipulate the viewpoints in AutoCAD to his/her preferences.

    If you can get your head around it

    Robert
     
    Robert Edgar, Jun 24, 2003
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  6. MO!

    MO! MOnkey`ead!

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    I'm thinking the system variables one is (B).

    I'm thinking that (C) is right for the coordinates one.

    Plenty MOre where they've come from :D
     
    MO!, Jun 24, 2003
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  7. MO!

    themadhippy seen it done it smokin it

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    :confused: i'll stick with turbo cad,tried playing with autocad 2000 last year,too complicated for a hippy
     
    themadhippy, Jun 24, 2003
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  8. MO!

    MO! MOnkey`ead!

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    erm......... :confused:

    I'm only on 2D so far!

    Also, am I right in thinking that Blocks use less disk space than if you were to simply copy and reinsert a part of a drawing that way? I know what I need to know about blocks (attributes etc) just not sure of if it uses MOre or less file space?

    Cheers MO

    :D
     
    MO!, Jun 24, 2003
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  9. MO!

    Robert Edgar

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    About Blocks Mo

    if you make a block of say a M20 bolt
    and you have 10 bolts in the drawing
    It still only uses the memory of the one bolt.....;)

    Robert
     
    Robert Edgar, Jun 24, 2003
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  10. MO!

    MO! MOnkey`ead!

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    :D
     
    MO!, Jun 24, 2003
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  11. MO!

    Robert Edgar

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    About Attributes
    Use the command ATTDEF to define them
    This is a dialogue box command
    So is pretty straight forward

    You just insert them like text
    Then when you insert the drawing you have created with
    the attributes in it,into another drawing thats what activates the attributes.

    Robert
     
    Robert Edgar, Jun 24, 2003
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  12. MO!

    Sgt Rock

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    Are we doing your homework ?
     
    Sgt Rock, Jun 24, 2003
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  13. MO!

    MO! MOnkey`ead!

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    Am I being charged for this? :confused:

    :D

    I've got my last lesson of the year tonight. Looking like I'm going to have to carry some of it over to next year though. Planning on doing 3D basic next. Should be interesting :cool:
     
    MO!, Jun 24, 2003
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  14. MO!

    MO! MOnkey`ead!

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    erm...... not exactly.

    On the course i'm ding it's all pretty much open book. It's three drawing tests and one multiple choice written one.
    I'm given a book with all the possible tests it might be. 1 set template to produce for part one, 4 possible drawings for part two and three, and 4 possible sets of questions.
    However, as it's only one evening a week, if there's something I leave the lesson not knowing (which is quite often the case), then i've got to wait till the following week to sort it out.

    It's not homework as such. Just an additional research tool. Not that i'm caling you tools :eek:

    You know what I mean.......

    I've done the first and second drawing test already. So with only one lesson left of this year i've still got the third and the mult' choice written one. I'm probably going to do the mult' choice one this evening. But, looks like i'll have to carry over the final drawing test as some of it I simply haven't had the chance to learn yet. It's not a class in the traditional sense of sit down and the lecturer dictates to you. MOre a case of go in and get on with it. If you need help you ask, though he does try to make an effort to see how we're all doing individualy.

    Cheers!

    MO
     
    MO!, Jun 24, 2003
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  15. MO!

    Sgt Rock

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    Just wondered if I needed to dig out :-

    BS 5070-1:1988

    Engineering diagram drawing practice.
    Recommendations for general principles

    It's been over 12 years since I was a CAD system admin :D :D :D

    I've still also got my Zeus tables somewhere :D :D :D
     
    Sgt Rock, Jun 24, 2003
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  16. MO!

    MO! MOnkey`ead!

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    Well, I sat the written test and got 13/14 right :D Got the damn system Variables one wrong! Only needed 10/14 so t'is OK though :D

    Had a look at the 3D stuff for the course i'm looking to start come september. Looks interesting! MOstly wire framing and applying surfaces rather than working with solids. I think it's the same lay out as the course I'm doing now with 2 drawing tests and one written. The drawing are of a house and a pen. You'd think the house would be harder but the pen looks MOre complicated with all the curves and such.

    Cheers for the help! Not just here but over on GH too :D

    Expect MOre Q's in the future :D
     
    MO!, Jun 25, 2003
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