6 Replies Latest reply on May 17, 2011 6:57 PM by Jeffrey Halsyon

    How can I prevent the need to 'Fix' things?

    Jeffrey Halsyon

      Greetings,

       

      Total newbie, here. I searched the forums and didn't find this info, which could mean I didn't search well enough, so if it IS already available, please just point me in the right direction. If you respond with an explanation, remember: I'm a newbie, so don't be afraid to use small words and explain things you think I should already know.

       

      The kicker on this is step 4, so you can just skip to there if you want. The rest is background/setup.

       

      I'm on the 4th tutorial in Solidworks 2006, trying to draw an oven rack.

      1. Drew the 135 mm line along X, then used properties to make it exactly 135.00 mm. Line Properties shows Fully Defined. The tutorial says to click on the start point, make sure it's coordinates are 0, 0, 0, and then click Fix (anchor) so it says Fully Defined, and it does.

      2. Drew the 15 mm line along Y, and Line Properties says Under Defined. I check the 'addititional' parameters and it starts at 135.00, 0, 0 (right on the end of the first line) and it ends at 135.00, -15.00, 0 (15.00 mm down), so I KNOW it's EXACTLY where it's 'supposed' to be. But remains undefined. So I click "Fix"

       

      So, I click "Fix" (The anchor) and proceed on:

       

      3. Drew the 15 mm line along X, and Line Properties say Under Defined. I check as before, and it's where it's supposed to be. I Fix as before (We're up to Fix 4, according to the Line Properties).

      4. Drew the 240 MM line along Y, and Line Properties say Under Defined. I check as before and Fix as before. Now a dialog appears saying we're OVERdefined and asks me to delete some defining dimensions or relations.

       

      Basically, if I go through clicking on the start point of each line, making sure it's on the end point of the previous, then using Fix to make them "Fully Defined" I end up with a sketch that's OVER Defined inside of a few steps. In all honesty, the tutorial didn't say to Fix it for any step beyond the first, so I'll try it with no fixing, but it made me wonder:

       

      What, exactly, is "Fixing" and how critical is it? I thought it basically 'connected' the lines by establishing a relationship, but if so, then why is my sketch OVER Defined inside of 4 or 5 lines?

       

      I tried doing things without fixing except on the first step, and everything looks OK so far. No idea what affect it'll have later. :-)

       

      Any info on what Fixing is would be appreciated,

       

      Jeffrey

        • Re: How can I prevent the need to 'Fix' things?
          Ajay Dhiman

          Hi,

           

          For Sketch Status follow below link it definately help you to understand sketch states and how to resolve errors.


          Sketch State

           

          and

           

          Find the attached video

          Hope this helps you...

           

          Thanks

           

          AD

            • Re: How can I prevent the need to 'Fix' things?
              Jeffrey Halsyon

              Ajay,

              Thank you for the video. I've been going over it step by step and I still don't see what you're doing and I'm not. I thought it was when you created the dimensions (the arrows that show the length), but when I create the dimensions I still show Under Defined. I'm going to figure it out, that's for sure.

               

              When I do, I'll post back and tell what I was misunderstanding.

               

              Jeffrey

               

              UPDATE - So, a part of the problem was that I was working with a 3D sketch (Lesson 4 of the tutorial). I tried doing what I saw in your video on a 2D sketch and it worked fine: I was missing the Dimension annotation. Thank you for your help, the video was what made it possible for me to figure out the problem!

            • Re: How can I prevent the need to 'Fix' things?
              Jerry Steiger

              Jeffrey,

               

              Fix does exactly that; wherever a point, line or curve is when you fix it, that's where it is stuck until you float it. (Same thing for parts in an assembly.)

               

              I'm not sure why the tutorial asks you to use Fix, as it wouldn't be my first choice. I would be inclined to add Coincident relations between the end points of the lines. Perhaps it has to do with the peculiarities of 3D sketches, which I rarely use.

               

              Jerry Steiger

                • Re: How can I prevent the need to 'Fix' things?
                  Jeffrey Halsyon

                  Erik and Jerry,

                   

                  Thank you very much for this information, it's really helping me comprehend Solidworks better.


                  The only reason I used fix in the first place was trouble closing the Under Defined sketch or something. I'm learning that while it has its uses, I should use it with caution.

                   

                  Thanks especially for the information on dimensioning, I didn't realize at all! And now I get to dig into the concept of 'floating'.

                   

                  This is one of the things I like about forums.. a question can be a little old and still get more information!

                   

                  :-)

                   

                  Jeffrey

                • Re: How can I prevent the need to 'Fix' things?
                  Erik Bilello

                  Jeffrey,

                   

                  Off the cuff , and without delving too far into the "how much fixing is to much fixing" debate (not much in my book), some of your problems may be the way you are dimensioning things.

                  You mention using properties to set the line length.  This will not put a "hard" dimension on an entity, I.E. you can still grab it and move it around.   You need to actually put a dimension on the line with the dimension tool (there will be arrows, extension lines and a number).  This will take care of the length part of getting your  line (technically a line segment) fully defined.  Of course you also need to define the location and angle (relative to something, put a dimension on it if needed) to have a given line fully defined.  You should seldom need more than one (if that) Fix relation in a sketch.  If you want/need to change something a bunch of fixed points will make your life complicated.

                   

                  With that said, and before anyone calls me on it.  Yes, there are situations where fixing is the way to go.  If you have a decorative organic shape that has no defined dimensions or locations, and few if any straight lines (signs for instance), get it to "look about right", fix enough points to nail it down and hope the artist approves your interpretation.

                   

                  Erik,