Projecting Geometry for a Loft

[dromani00]

Good day.

I'm having some difficulty with getting a loft to turn out correctly. In the following figure, I've created the loft with two profiles and the yellow highlighted rail.

It appears to be exactly what I'm looking for until the loft is examined from below; I've highlighted the loft bottom surface and the mating surface. You can see the discontinuity easily. I'm trying for a smooth intercept so it looks like I need to specify a bottom gide rail as well as the upper one.

I've created a sloped plane and 2D sketch for the bottom rail, but when I project the upper rail geometry onto the sloped 2D sketch, it projects perpendicular to the sketch/work plane instead of perpendicular to the original projected geometry.

Is there a way to tell Inventor 2014 to change the projection from perpendicular to the sketch/work plane to the perpendicular of the geometry being projected?

I've attached the part for your consideration.

Thank you.

[Anonymous]

Don't know if this is what you want to do, but if so, it can't be done in Inventor at this time. I think I remember seeing a wishlist item about this very thing on the Inventor Idea Station.

[JDMather]

The rail is a simple 3D intersection curve of two 2-D sketches.

[dromani00]

The distortion would be what I'm after actually: An arc projected onto a slanted plane. In this example, project the top rail (Highlighted in yellow in my original message.) straight down onto the slanted sketch plane.

[dromani00]

This may be true, but your response does nothing to explain the how to do that projection.

A bit more verbiage on the how, would be appreciated.

[JDMather]

I suspect you don't really want this line horizontal as you have sketched it, but take a look at the attached file and is it something close to what you are after?

[dromani00]

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@Anonymous wrote:

I suspect you don't really want this line horizontal as you have sketched it, but take a look at the attached file and is it something close to what you are after?

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You are quite right, I saw that after I'd already posted the original message. After the head slap I gave myself, I corrected it to follow the original arc.

Also, the ZIP file containes an .stp file type which identifies as a 3dsMax file. While I have 3dsMax, it doesn't like this file. It's also only 47K in size. Did this get saved to an incorrect file type?

[JDMather]

STEP (*.stp) is a commonly used neutral format CAD file that can be read be most any CAD program.

Simply right click on the *.zip file and select Extract All.

Then in Inventor set to Open files of type STEP (*.stp) and open the file directly in Inventor.

If this geometry is close to what you are after - I can spend more time on a correct solution.

[dromani00]

Thank you. Yes, I see the result, and it is what I'm looking for, but I do not see how you did it.

Can you please explain what you did?

[JDMather]

I did a little more work - anticipating your end goal.

Is this where you are heading (see attached file)?

[dromani00]

Yes, that's where I'm heading, but I still have no insight into how you went about it.

Can you please explain?

Thank you.

[JDMather]

I have never modeled a part using the techniques that you use - so it will be this weekend till I have a chance to clean up my model enough to post on a public website.

[dromani00]

While you have provided the solution, it's not what I'm looking for. I need the how. How did you generate the corner curve correctly.

Providing the solution, doesn't help. I need an explination of the method used.

THank you.

[dromani00]

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@Anonymous wrote:

I have never modeled a part using the techniques that you use - so it will be this weekend till I have a chance to clean up my model enough to post on a public website.

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Humm... Well, then that begs the question: How did you do it? If it's more efficient, I'm all for it.

Thank you.

[JDMather]

I just need to recreate from scratch solution and then I will post the file with history tree.

Check back in a bit.

[JDMather]

I spent 8 yrs out on the shop floor - so I tend to think in net shape or near net shape - Design for Manufacturability.  How am I going to make this thing, or the tooling to make this thing?

Given that mindset - my solution might not match what you are after as I was really confused by the dimensions (I am used to seeing simple numbers, I even tried changing to mm to see if they would make sense to me ) - but in any case, atttached is my "solution".

I added a fillet that wasn't in your part.  It can be removed with a Ctrl Click on the edge.

[johnsonshiue]

Hi! I took a quick look at the part to get the sense of design intent. If seems like you are trying to replicate geometry from another part. If I were you, I would remove those fillet faces first (Delete Face -> Heal). In that way, you can deal with simpler profile and worry about rounds later.

Do you want to make a flat pattern from the part? If yes, I don't think the finished part would be unfoldable in Inventor right now.

Thanks!

[JDMather]

Have you been able to figure out a solution to your problem?

[dromani00]

Not really, no. While I do appreciate the work you did, I have no idea how you got there. So while it is a solution, without an explanation, I can do nothing with it, nor repeat it in the future.

Thank you.

[JDMather]

The entire story of how I got to the geometry I posted is in the feature tree.

That is the real power of parametric modeling - the history is preserved for study.

That is basically how I learned Inventor.