Fillet going the wrong way

[Anonymous]

In the attached pic, I have between trying to draw a fillet  but Autocad has extended the line and turned the fillet upside down.

Can you please tell me why this is happening?

Thank you

[Patchy]

Your is not Not World UCS, as it said on the Right of your screen.

[nestly2]

My initial thought was the constraints or the pick points.   Are those constraints there by design, or is AutoCAD just adding them as you draw?  (no right or wrong answer, I'm just curious)

[Anonymous]

Thanks for the thought on that Patchy. I did some fillets at the top of the line forms which did go the right way by I will take that into account.

[Anonymous]

Thanks Nestly2.

This was an exercise to draw in the isometric using a rectangle and some lines (Autocad 2015). So, I drew this basic shape of my favourite flange (which seems to uncover all the flaws in my methods

Now, I've been conscious of my need to be accurate so, I firstly put parametric constraints on the relevant lines to make them parallel to the x and y axis. I then made the lines approximately the same length symmetrically around the shape and joined them to each other coincidentally.

The idea was to find a way from there to add fillets and thickness to the resulting rectangles and this create the solid I call the flanged plate.

I put fillets on a couple of corners further up and this resulted in the lines that formed and edge there being isolated. Those fillets were correct. The one further down and the subject of my image, came up with a fillet upside down and a message saying the radius was too large. At that point I wondered whether the fillet was trying to get into a smaller angle.

I used to be a paper drafstman so getting my head around a CAD is proving challenging because in the paper 2D plane you draw in 1st or 3rd angle projection and then the isometric is drawn to reflect those views.

Hence when I looked at the World UCS I didn't think it was all that different to what I did on paper in the drawing office.

[JDMather]

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@Anonymous wrote:

.... in the paper 2D plane you draw in 1st or 3rd angle projection ......

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I simply use the 2D drawing methods I learned on the drawing board back in the last century in the 21st century CAD tools.

I would draw profile.

Extrude surface body.

Thicken to a solid body.  (let the CAD program take care of creating the 3D for me - all I have to do is use my 2D drawing board skills)

Let the CAD program (I use several different CAD programs) generate the top, front, right side, isometric, section, detail.... whatever views I need.

Before I start to work up some examples - what are your intended units (Inch, mm, cm, m, ft....)?

Is something like the attached what you are after?

[BrianBenton]

It's difficult from the image to determine what's going on. Maybe there is an extra line in there that you actually picked? Or in what order and position did you pick the lines? Picking on one side or the other of a line will determine the direction of the fillet. If you could attach the DWG file we could take a look at it to see if there is something strange happening.

[Anonymous]

Thanks JDMather, I tend to do the same though for the purpose of the exercise, I am trying to stay within the Autocad 2015 playing field.

I was originally extruding after I had mirrored the top and bottom half of the plate. I ended up extruding too far and then couldn't bring it back except with pushpull. This then resulted in the parametric constraints being lost from the end where the extrusion started. There were real prblems with this extruded shape because of thickness variations and the inability to put holes through it for various reasons, including alignment with the X and Y axes and the direction of the Z axis. So I was trying a different approach.

I am currently running on the 2015 trial version of Autocad which will expire today so will see if I can get an extension. The Polysolid function may be able to help make the flange though I think, based on what I am reading, it is easier to do in Autodesk Inventor. Still, the challenge to do it in Autocad, at least for me, remains.

[Anonymous]

Please find attached file. I think it is the way I am going about this Patchy. I think in 3D but its still a 2D XY Drawing and that I think is why it doesn't work.

My trial on Autocad 2015 is running out today but I will monitor the forum.

Thanks!

[nestly2]

I know it's probably too late, but I think Patchy had the right idea.  From what I can tell, at least one of the objects was likely a Polyline, and Polylines are can only exist on one plane.  FILLETing a PLine with another PLine (or a Line) will join the two obects, but it will only be successful if result is still defined by a single plane.