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  • Selecting edges in assemblies?

    Discussion in 'SolidWorks' started by thebigconsultant, Sep 9, 2011.

    1. thebigconsultant

      thebigconsultant Active Member

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      Hi,

      I have used SolidWorks for a number of years, but I am having an odd and annoying problem that I cant find the solution for easily.

      Doubtless, some of the users here might have the solution.

      [​IMG]

      Here I have a large grey block in an Assembly. Its just going to be a machined nylon piece for a Jig.

      The 'rocket' shaped parts are the components that I wish to locate into the jig, and I want to make a machined profile that will hold these in a cavity. With say, a 0.1mm offset edge so that they fit in the jig nicely, without 'jiggling' around.

      Problem is, and I have had this before, that when I try to use AutoDimension to select the black SketchLine that I have drawn, the damn system wont select the outline edge of the component part that is in the Assembly.

      The 'rocket' shaped component part is a SubAssembly comprising of two acrylic parts. They are transparent, but usually selecting ALT allows transparent faces to be selected. When I try to select the edge of the rocket shape, and dimension to the sketch line, the system wont select the edge of the component.

      I keep coming up the this problem, when working with assemblies, and I have never been able to work out why this happens. Can anyone help??

      Cheers, Bid
       
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    3. GarethW

      GarethW Chief Clicker Staff Member

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      This kind of thing happens quite often to me and drives me crazy. Sometimes I get around it in either of the following ways:

      a) Sometimes it will allow me to actuall place a point on the line (even through it won't allow me to dimension from it :? . Even though it might snap to the line it won't actually be constrained so I'll then "fix" it in place then dimension of that.
      b) Open the part that's being difficult and break its external constraints!

      There are probably much neater ways of doing this and I would also like to hear them.
       
    4. GarethW

      GarethW Chief Clicker Staff Member

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      Hi Bid, did you manage to get anywhere with this at all?
       
    5. LesH

      LesH New Member

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      Have you checked your settings in the system options under Display/Selection?
      You may have to select or deselect one of the settings under 'Selection of hidden edges' or the 'Enable selection through transparency'.

      Hope this helps
       
    6. Michael Davis

      Michael Davis Member

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      A couple of ideas that may help:

      Working with parts in sub-assemblies in an assembly can be tricky. They tend to answer to the above kinds of issues only when the sub-assembly is in edit mode and you are dealing with a part in that sub-assembly.

      That said, putting control sketches in implies you are creating a part. Otherwise, a sketch is not a control feature but a reference feature. If you create a new part in the sub assembly, then another issue pops up: that being that relations are mate driven not dimension driven. Put the dimension from one part to another by creating a second part from the sketch and then using the dimension aspect in your mate menu.

      That said, keep in mind that dimensioning from edge to edge is an inconsistent and unreliable way to control the distance. Use coincident plane mate from the center plane of each part, assuming you have created the part from a center plane, which in general is always the way to go when creating and controlling part locations.

      Finally, there is another way to do this: create a single part model, i.e., the assembly has all the parts in one part, then peel off the bodies of the features of that part as an exported body, which can then be used to create digital machining data for the cnc tooling operation. (use 'insert into new part' when right click selecting a body in a single part assembly). :ugeek:
       
    7. tbearu

      tbearu New Member

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      Have you tried to to create that sketch by offsetting the part edges? By doing so, you can specify your desired offset value and also you will be sure the new created geometry will respond to any future part modification!
      I had in the past problems selecting edges and I think it can be related to the graphic card and display settings. Check and install the latest driver for the video card and always use the recommended SW video cards.
      http://www.solidworks.com/sw/support/vi ... sting.html
      Regards,
      TB
       
    8. thebigconsultant

      thebigconsultant Active Member

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      Still no closer on this...

      Its seems that sometimes you can select edges and sometimes you cant select or offset them.

      Its very annoying, and I cant find an explanation for it anywhere. I have SW set to load everything as fully loaded and not 'lightweight'.

      I think I read somewhere about a pressing the control key, or something like that to access edges that dont want to be selected. But this does waste a of of my time, as I have to manually dimension things! :x
       
    9. tbearu

      tbearu New Member

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      Yes, it is annoying! As another step, switch to wire frame and try.
      I am still inclined to think this behavior is the result of the computer video hardware . If you think your computer configuration is ok, roll back one by one the created features, delete colors and appearances (transparency in particular) and try selecting the culprit edges. I am sure you will figure out which step got you into trouble.
      Also you can re-create the part from scratch as the last resort to see if it can yield different results.
      Is this only part creating you problems? It is from an imported body?
      Regards,
      TB
       
    10. srdfmc

      srdfmc Well-Known Member

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      SW does not work well that way (dimensioning on edge). On the contrary Catia does. You might loss the relation during subsequent modification.

      The best way to do it:
      1- offset the face using surfaces working tools
      2- If you need to work that way in the part : create a colinear segment (property set to colinear) and add dimensions using this segment.
      3- Additionaly the classical way to do this in SW/Catia is to project the shape in the draft and add a dimension to the new segment

      Methods 2&3 generate a high rate of geo property loss (much higher under SW) and are not usually recommended.

      In anyway make sure you use the edge filter to properly and easily select an edge out of a draft.

      0.1 mm Hummm Laser cutting ? ;)
       
    11. epochdesign

      epochdesign Member

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      This is a problem for me too. I've been using SolidWorks since the begining and I can say that this is a problem that just arrised in 2011. No setting changes this and it is completely arbitrary. Sometimes you can use "select other", other times you need to isolate the relevant parts and sometimes even that doesn't work. It's BS.
      It's otherwise a great tool, but I've recently quit my 16+ years of subscription service in protest to poor way they treat long-time customers. Please let me know if you find a workaround.
       

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