Full Version: Fillet Problem

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Hi Sharif,


A problem with non-planer curves.

Trim off the curves and use blend. I usually use a circle for trimming.


- Steve

Image Attachments:
trim-blend.png 

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Thank you!

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Hi Sharif,

> Is the fillet in this condition not possible in MOI?

It's not just a MoI problem - the curve fillet for that case is actually not physically possible at all...

The way curve filleting works, is it tries to put in an arc of your given radius that is tangent to both of the curves.

If the 2 curves are not in the same plane, there is typically not any such given arc that exists, it's too easy for the tangents to be going in different directions. In order for an arc to be possible the endpoints of the arc and end tangents of the arc must all be in one plane.

This may be confusing because you may think what about making a solid edge fillet something like this:





But even though this looks like a curve fillet above there, that edge is not actually an arc, it's kind of a slanted cross-section of the fillet surface.

If you turn on surface control points of the fillet surface you can kind of see how the fillet surface is larger than that piece and that the rounded corner is actually a kind of slanted slice out of a larger rounded corner surface:



So since it is not physically possible to make an arc fillet in that situation you probably want to do a blend technique like Steve shows - unlike curve filleting, blending does not require the end points and tangent directions to be all in a single plane.


Or depending on what you want in the end you may not want to try and make a curve fillet in the first place but instead wait to get an edge fillet later on as above.


- Michael

Image Attachments:
sharif_fillet1.jpg  sharif_fillet2.jpg  sharif_fillet3.jpg 

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Hi Michael;

Thanks for clarification and explanation. Sometimes I look at the tutorials in other modeling application and try to replicate them in MOI. it is a great way to learn the application. In this case I was watching this video tutorial (http://www.formz.com/webinars/webinars_html/chaise_lounge.html) in Bonzai3d to build the Le Corbusier chaise-lounge furniture in MOI. In bonzai3d with fillet command you can fillet corners in this condition as they were showing in the video. The model was very easy to build in MOI except that I didn't know how to fillet the corners between the arcs and line which with Steve' solution it works perfectly now.

Thanks

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Hi Sharif,

> In bonzai3d with fillet command you can fillet corners in
> this condition as they were showing in the video.

Well, it sort of does but not quite exactly - after watching that video I gave bonzai3d a test to see what it does in that situation (since there is no actual true fillet arc that can work there), and I found out that it creates a blend spline curve in to make that rounded corner.

That could be a potential problem, because it actually says the mode is "circular", yet it builds a kind of generic spline curve piece that is not actually an exact circular arc...

It could be convenient though to have fillet do that, but maybe not in some way that could fool you into thinking you had an arc when you do not, like maybe that could be enabled in MoI if you set the fillet Shape: option to be a blend shape rather than a circular shape.

- Michael

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Hi Michael;

Thanks for clarifying it. I didn't try this problem in bonzai3d, because The trial version of software I had was expired. I watched the video and I thought that was an arc fillet. I totally agree with you and will be nice to have that option in MOI.

Thanks

-Sharif

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