Fillet problems

[evanp4509U4JZ]

Can someone tell me how to fillet the edges of the bottom flat surface of this part to .178"? I keep getting either the "edges undefined" or "try changing size" excuse for not filleting it. I'm trying to recreate the mesh in a 3d part I can machine. Is there a better way? and how?

Thanks in advance

[TheCADWhisperer]

Would you be OK with starting over from scratch?

[evanp4509U4JZ]

Sure, why not. 4th times a charm. lol What should the proper work flow be? I got it to work by sketching on the bottom, extruding .05" to cut to remove the lateral lines that I have no idea the origin of and then combine extruding that surface up .05" to create a smooth bottom and then remove the .05" surfaces created on the perimeter and then fillet worked fine. I then removed faces on the top to get it to only 4 surfaces and then fillet worked there. 

I'm sure this is akin to building a car to get across the street. I've only been on this project about 15 hours. How long should it take someone competent? Just curious.

Here's where I'm at now which is as close as it needs to be for this but I'd love to know how to make the model exact to the mesh in less than a lifetime or so.

I am quite computer illiterate but I'm assuming all those squiggly lines means something bad.

[jeff_strater]

yeah, the problem with this model is that that bottom edge is not tangent continuous.  These "near tangent" geometries causes Fillet lots of problems.  So, if you can make it so that those edges are constrained to be tangent, it will help.  Also, the bottom face is a bit of a problem as well.  That should probably be one single planar face.

[evanp4509U4JZ]

Tangent continuous??? Sorry, not a CAD person. More of a weldor that got "nudged" into CAD.

How I developed that sketch was to insert the mesh, arduously align the mesh with a plane, "create mesh section" from the sketch menu, "fit curves to mesh section" in sketch menu with splines that seem to create redundant overlapping lines, and "fix" the gaps in the sketch with freehand sketching that seems to take an eternity to create a closed sketch as lines refuse to snap to what I think are end nodes for other lines and then "trim" all the redundancies at maximum zoom as they do seem to actually overlap.

As I said, I'd love to know the right way to do it.

[TrippyLighting · Accepted solution]

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@evanp4509U4JZ wrote:

I've only been on this project about 15 hours. How long should it take someone competent? Just curious.

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I believe I can do this can be done in 2-3 hours max as it's a relatively simple shape.

I'd use the scan only as a visual guideline and use a  surfacing approach by approximating the shape with curves from and then I'd build surfaces from these curves. It's somewhat similar in approach to the technique I use in this video where I helped another user with another box-like shape.

[jeff_strater]

sorry for the terminology.  I never know who I am dealing with - some people are pretty familiar with CAD concepts, some less so.

By "tangent continuous", I just mean that each edge flows mathematically smoothly into the next.  From a sketch point of view, this is done by applying a Tangent constraint to adjacent curves.  It just so happens that geometry which has this property is more easily filleted than geometry which does not.  Anyway, take a look at @TrippyLighting's video for some suggestions.

Jeff

[TrippyLighting]

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@jeff_strater wrote:

sorry for the terminology. 

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You should by all means continue to use "terminology". 

Tangency is easy enough to look up. And a strikingly simple concept.

[evanp4509U4JZ]

Thank you. That's awesome. I've only used the model and cam environments until yesterday and the mesh one only then for the first time. I noticed you use remove where I would instinctively use delete. What is the difference and where would you use one over the other? I also noticed the sketch uses abrupt line intersections and the filleting or radiusing is done on the model. I was going the other way. Your way looks much better.

Again, thank you.

[evanp4509U4JZ]

Thank you. Asking and answering is where all the learning happens. I now have a new piece of knowledge and hopefully wont have to ask the next question with words like thingy or doohickey.

[TheCADWhisperer]

As a beginner - I recommend you avoid splines for a while and stick to lines and tangent arcs.  Always be aware of symmetry in your design.