Inventor Nesting - Part imported wrong side up

[They_Call_Me_Jake]

A colleague and I are trying to solve an issue happening with Inventor Nesting. We start with a multi body part and make our assembly from that. Our parts have mills and pilots in them they have to be cut with specific faces facing up so after adding all the details to the parts we make an assembly and place all the parts in the assembly with the face we want up facing Front. We then Create a Nest using that assembly. When looking at the 2D view of the source files in the Nesting Add-In everything looks fine but if you switch over to the 3D Detailed view you can clearly see that the part was brought in with the wrong side facing front so after we do the nesting study we do a 3D Extrude on the nested sheet and when it uses the original part for the 3D model it is flipped back side to front. We have tried just about everything we can think of to force it to pull the part in with the correct orientation but nothing seems to be working. We have even tried the Nest Authoring using an unconsumed sketch as the last item in the design tree but it still pulls the part in upside down. Does anyone know a work around or a way to force which face is chosen to be up when the part is derived from an assembly made from a multi-body part?

[Anonymous]

Are these sheet metal parts? If they are you can use "Define A-Side" to say which side is up

[They_Call_Me_Jake]

@Anonymous Thanks for the fast reply. No these are not sheet metal parts.

[Anonymous]

Are you able to share your part(s)? I just made a sample part that was directional and making a new sketch on the top face and projecting geometry did it for me, but I can try with your parts.

Guess I should ask what version you're on, I'm on 2020 at the moment

[They_Call_Me_Jake]

@Anonymous I am on version 2021

[Anonymous]

I have 2021 on my machine, just don't use it for production work. I can still take a look at your file

[They_Call_Me_Jake]

@Anonymous  I think I may have found the cause but am unsure of how to change it. I checked the normals of both the front and back face and they are both at -1 in the Z direction which is the direction I need it in but in the positive. All of the parts that are facing the right way has the front face at positive 1 in the Z direction. Is the a way to change the normal of a face?

[Anonymous]

Are you saying that you think one face needs to be oriented toward the positive Z axis? I don't think that is necessarily the case because I was able to flip one without messing with any axes or orientations

[They_Call_Me_Jake]

No...I think that both the front and rear face need to be flipped.  I tried my theory on a generic part that the sketch was on a workplane created from an origin plane. When extruded normally both the front and rear face were in z positive direction but when I flipped the plane and extruded normally both the front and rear plane were in the negative z direction. Problem is that it's not an easy thing to just go into the parts and flip planes as thing tend to break when I do that. 

[Anonymous]

I don't think there's a need to go about messing with that

[They_Call_Me_Jake]

then what's the solution to my problem

[Anonymous]

Post your part and I'll take a look at it to see what can be done at the part level

Without seeing the file and if the sketch doesn't work for you, you could make sheet metal rules and define the A side, export the face as a dxf and import the dxf files, or select mirror in the nesting properties to flip it over

[They_Call_Me_Jake]

I think I may have found a solution. It appears that if I have the face I want pointing up in the Inventor Nest facing the positive Z direction then the Solid Body gets imported into the nest the correct way. So I am going to make a copy of all the parts I want to nest and then look at which way the face I want pointing up is facing and if it's not facing positive Z then use the Move Feature to rotate it so that it is. Of coarse all of this will be done with code.

[They_Call_Me_Jake]

Unfortunately I can't share the part I'm having trouble with due to company rules about sharing files. I'll see if I can reproduce the problem on a generic part because the solution I thought I came up with did not give consistent results so I can't rely on it. 

[They_Call_Me_Jake]

@Anonymous I was able to duplicate the problem with another part. Here are the steps in which we make our parts. We start with a multi-body part "MultiBody Test.ipt" then we use Make Components to create an assembly "MultiBody Test.iam" from which we can do all the other things needed. Once it's ready for nesting we insert all of the parts into a nest assembly "Test Nest.iam" where we would manually nest our part. In "Test Nest.iam" you will notice that the part "Test Door.ipt" has the side with the circle facing toward the front as this is the side I want to have up when it's cut on the cnc router. When I right click on the "Test Nest.iam" in the design tree and select "Create Nest" it appears to import into Inventor Nesting fine but then after I make the nesting study I right click on the sheet and click on "Create 3D Model". I make sure to have it use the 3D Source if available and I uncheck "Include Stock". When it creates the 3D model it does bring in the source parts but if you notice the "Test Door.ipt" that it uses now has the side with the square facing forward instead of the side with the circle which is the side we want facing up. I used the preview in the nest authoring utility and you can see that the back face(the one with the circle) is being projected thru the part to the front but the actual model is being import wrong side forward. I know I can change the direction of the extrude using the nest authoring and that does work but all of this is being done with code and there is no way that I've found to indicate if a part will be imported with the wrong side facing front until after you nest it and then do the 3D Extrude. I thought that by doing a move/rotate of 180 on the original part would work but it doesn't work all the time. If there is a way to know if it will import wrong face forward and then a way to change the extrude in the nest authoring I could live with that. I have found that by making the part a sheet metal part and making a flat pattern works also but the 3D model it creates is actually surfaces and it's not a solid model which we need for the type of programming we do so we would need to import the original part into the nest and constrain to the surface model . If you have a way to solve this issue I would be ever so grateful.

[Anonymous]

Thank you for attaching these and for the explanation. I will take a look at them here shortly. Do you have the inest file as well? You may have to zip the inest file as I do not believe the forum supports it as a file extension.

[They_Call_Me_Jake]

@Anonymous Here is the .inest file. Another thing to note is that it shows the circle as a cutout clean through the part instead of what it is which is a pocket .125 deep in a .5 piece of material. This has it's own issue in that Inventor nesting now thinks this is an area it can nest smaller parts into.

[Anonymous]

Took a look at your files, what you're doing looks to be more like needing a milling operation(3D cut) as opposed to a 2D cut like a laser or waterjet. Because Inventor Nesting is intended for sheet metal parts that do not have unique features on both sides, it is going to pull one face or the other. I think you're getting "lucky" when you export the 3D model because it is using the original components, therefore showing both unique sides. All this to say that nesting parts with 2 unique faces might be a limitation of Nesting. @johnsonshiue can you confirm if this is a limitation of Inventor Nesting?

[They_Call_Me_Jake]

This is true....we do cut these parts on a cnc router and the CAM program we use, uses AutoCad layers to determine the bit to use along with speeds, feeds, cut type and so on but with our company each of the design engineers also does the programming for their parts so each engineer nests all the parts for their project together in one nest and then all the nests are sent to the CAM software that will nest all the nests together according to material. we just trying to automate the nesting process for the individual projects because it's takes quite some time on some of these projects to nest all the parts together. If there was a way to figure out which side the nest authoring was grabbing in the original part we could automate the process of reversing the direction of the extrude in the nest authoring. do you know if there is any way to see what side it's grabbing? 

[AmyLiu]

@They_Call_Me_Jake 

This flip doesn't work should be an issue, logged already in TRUNINV-2189; we will try to fix it ASAP and then update you.