Add a "Negative" radius for clearance

[karthur1]

When providing for clearance in corners, we are sometimes required to provide for a "negative" corner radius.  Presently, Inventor does not allow for this and we have to use other means to place this feature (new sketch and extrude, ifeatures...etc).  I would like to be able to either enter a negative value for the fillet, or have an option in the fillet command to run the fillet the opposite direction.  In the image below, I show the "negative" fillet.

Thanks,

Kirk

[kim.schroeder]

Excellent idea!

/Kim

[jdchakes]

I would also greaty benefit from this feature

[asiu]

Great idea!

Adrian

[Heathos88]

great idea, need this also

[Laurens-3DTechDraw]

I like the idea but wouldn't drawing a circle and trimming the excess do the trick?

[karthur1]

I like the idea but wouldn't drawing a circle and trimming the excess do the trick?

Sure you can do it that way... that's the way I do it now sometimes. When you want to add a fillet now, do you draw an arc in the corner and extrude cut the material away.... probably not, you use the fillet command b/c its more efficient.

I think it would be more efficient to be able to do this with the fillet command also.  You could quickly pick the place that needs the clearance and enter a negative radius and you would be done.  Just like you do with a fillet command now.

[Laurens-3DTechDraw]

No I wouldn't make a fillet that way, but to be honest I think fillets are used much more then these internal round cuts.

Also a problem would be the definition of the fillet. Cause it's a rounding of a corner, sometimes also called blending of a corner, so what are doing is maybe something like the opposite of a fillet.

[karthur1]

"......so what are doing is maybe something like the opposite of a fillet"

Exactly,..... a "negative" fillet. 

[Laurens-3DTechDraw]

"Exactly,..... a "negative" fillet."

Is that something like Negative Mass?

I meant more like is the fillet feature a good place for it.

[lesmfunk]

I think the fillet command is the best place for it. I would use this feature often.

[Delmeco]

Why ain't it possible to create a inverse fillet. Now we have to draw a sketch an make an extrusion.

It would be so easy if a button was add to the fillet command with the "inverse fillet" option.

[admaiora]

Hi Delmeco,

you have my vote.

Meanwhile you could find useful this tread for a quicker workflow.

http://forums.autodesk.com/t5/inventor-general-discussion/need-to-add-a-quot-negative-quot-radius-fo...

[kim.schroeder]

This is a duplicate idea - original to be found here:

http://forums.autodesk.com/t5/inventor-ideastation/add-a-quot-negative-quot-radius-for-clearance/idi...

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[Delmeco]

I posted a similar ID, didn't search for others.

Optionally add an offset to faces to make it possible to place the center where wanted. 

[scottmoyse]

Man I have wanted this so often in the past.

[stephengibson76]

I have asked for this before on the forums but not here...  It would be very useful to me also, indeed anyone who welds aluminium....  There was another comment, not related but in this thread about negative mass, this would also be very useful to me for assembly centre of buoyancy 

[SerkanCicek]

What about creating and using an appropriate iFeature? It sounds better to me, because it is not a fillet, rather it is a relief, isn't it? I mean, you might need a circular relief but one might need a rectangular one or a smoother one.

In addition, having a negative value doesn't make sense to me. What will be happen when you retrieve this dimension to a drawing? Will it be seen as "R-.25" ?

[karthur1]

What about creating and using an appropriate iFeature?  I currently have a 1 and 2 place ifeature for this.  Its just more efficient for me if I could do it with the fillet command.  Most of the time, for me, they are fillets. I can only think of one instance that it was a rectangular shape.  Those are usually avoided because that creates stress points.

What will happen when you retrieve this dimension to a drawing? Will it be seen as "R-.25" ?  No, it will show as R.25.  I am sure that can be handled in the code.

Look at the number of people above that want this feature or have given this kudos. I think they agree that it would be useful.

[SerkanCicek]

Look at the number of people above that want this feature or have given this kudos. I think they agree that it would be useful. I aggree, but so? Does having more than 100 kudos mean that the proposal is absolutely right?

Whatever, personally I don't support having this feature inside the fillet command. It is not a fillet, it is obviously a relief. I think, a similar application of two seperate features should not be combined into one command. The important thing here should be the function or the physical meaning of the feature.

I think there might be an additional command for this purpose including different geometries beside the circle. Additionally, maybe it would be better to have more options like offset. One might want the relief positioned exactly on the corner, another might want it to be offset.

[karthur1]

I agree, it is a relief and other options could make it more useful. I thought it would be really easy to add this to the fillet command, but if you want to broaden it into a new command that has even more options, then that would be great too.  I just think that there is a number of users that could benifit from this type command.