Inventor 2017 - loft problem

[Anonymous]

Hi all, hope someone can help.

I have a simple part for a bathroom spout (or faucet if you prefer).

The issue I have is that when viewed from above the left hand edge is slightly different to the right hand edge.

I have illustrated this on the attached image and the part is also attached.

I have checked the sketches and  cannot see anything which might cause this.

Thanks

[CCarreiras]

Hi!

It's a Inventor bug, like more others it have in surfaces.

Now, my question is:

do you need a way to solve your model, i can help you.

If you want to solve the bug.... it's better send your model to Autodesk Teck guys.

[Anonymous]

Thanks CarlosC,

I have come across similar before and the way I "corrected" the model was to cut it in half and then mirror the half that was left, this at least made it symmetrical.

If you have another way of correcting it I would be interested.

Regarding the Autodesk Tech guys, where do I send it?

Thanks

[CCarreiras]

Here's your symmetric part...

[phaeronkor]

Hello Carlos!

Can you tell please, what have you changed to get right loft size? Cause it's interesting for me too 😃

[Anonymous]

Thanks for your model Carlos, but your version has a "seam" along its top face which won't look too good further down the line when rendering chrome finishes etc.

I would also like to know what you have changed, but I'm not sure your solution works for me.

Thanks

[CCarreiras]

Of course you will have a seam.

This is due your loft rail. Your loft rail is forcing the geometry to make an edge down.

Let me try another version.

[CCarreiras]

Like i said.... if you smooth the upper rail, the loft will be perfect.

[phaeronkor]

Thanks, Carlos!

But why in your 1st answer when I highlight the body it shows me that it's consists of 2 edges?

[CCarreiras · Accepted solution]

Let me try to explain....

When you start the loft, Inventor create automatically a edge in a side (blue arrow 1), not the better place to have the edge if you want to have a symetrical part regarding the vertical plane as mirror. The lateral edge is good to achieve a part which is symetrical by a horizontal plane, which is not the case of this part. so, the part is "kind of" divided horizontally, and that's why you have different sides on the part, as you notice in your first post. Picture on the left.

So, the aim is to achieve a new condition that "move" this edge to the top, and due that, the part will be symmetric by the Vertical plane, so, the part will be symmetric by this plane, and both sides will be equal (symmetric).Picture on the Right

To achieve this, I first divide the profile sketches (turn the circles in arcs) to have new points for loft use as anchor, but the top rail is as a shape too "bold" to mantain the surface continuos, so, we got the edge on the top (good), but an unwanted shape at the top (bad).

In second attempt, i just edit the rail to a more "friendly" shape and it works well. Edge on top and a continous surface. (So friendly that i did not even have to divide the circles)

[phaeronkor]

Aaah...Now I see, I didn't notice that you've divided circle in parts.

Thanks a lot! Hope your answer satisfies WaynePriest's needs 😃

[Anonymous]

Thanks Carlos,

I think I understand what you are saying, but still think its an error that inventor shouldn't have.

Wayne

[CCarreiras]

This is not an error.

Inventor can't "guess"preciselly all you want do, so, it chooses a place to have that edge (*), sometimes it choose a good place for what i am doing, sometimes, not.

Therefore, is up to you to find conditions to force inventor "guess" what you're trying to do.

In Sum, sometimes with a few information, inventor gues what you need, sometimes you have to give more information about what youre trying to achieve.... and that's it, is not a error.

(*)and some other things like the positive side/direction of sa surface, the system coordinate of a new face, etc etc.