Struggling mesh to solid

[RScott9399]

I have a very detailed and complicated mesh of car body. Fusion will not make it a solid. 

All I get is endless "cant compute errors"

I am trying to make a simplified mesh. All I am really after is the outside shell so I can 3d print it or slice it up and mill it on a CNC.

It seems the only change in hell I have of getting fusion to cooperate is to drastically cut all the detail of the model out. It has a full interior of the vehicle as well. So what im trying to do is figure out an easy way to delete all the parts I don't need. I have tried to do a manual edit but good luck. I will be here for 3 centuries deleting triangles. 

Fusion has created face groups which look to coincide with the major body panels which is mainly what im after. 

Does anyone know of a way I can somehow select only the outer face groups and delete everything else in the hopes it will make me a solid?

Thanks

[RScott9399]

Do I dare ask what convert it to fusion curves means?

[RScott9399]

I have seen something similar to what you propose but not sure how you make "fusion curves"

[davebYYPCU]

Create Mesh section sketch.

edit sketch > fit curves to mesh section.

Might help......

[RScott9399]

Cool, thanks

Learning more! 

So I created a mesh sketch. How can I extrude it though. Hitting Q like normal does not work in this case. The sketch is open ended as and not a closed loop. I image that is. So I wouldn't be able to do the car in sections at first. I would have to produce a closed area to extrude I imagine. Sound correct? Thank you!!!

[RScott9399]

k stuck again, so how do I extrude a mesh sketch? I don't see an option for that?

[davebYYPCU]

Create Mesh Section Sketch

Edit sketch > Fit Curves 

Hide Mesh section of the sketch.

finish contours for a closed loop

(Line command - put a line from one end point to the other end point of the open loop.)

It is now a normal Fusion sketch, blue shaded ready to extrude, but you don't need that extrude for CAM, which will handle just the sketch.

Might help.....

[RScott9399]

Thank you 

so I have gotten almost all the way. 

I am have a problem finding a way to reference all the the points from what will be all the sketches to keep everything aligned. 

that’s a different topic. 

Since the bottom of the body she’ll is an open shell, as the back of the car body raises up I no longer have a ground reference. 

I tried created a mesh that was sort of like a ground plane and trying to join the meshes so when it does the cross section they all have a common “floor” to connect to , to close the loop. 

however two issues have arise. 
One, when I exit the mesh sketch, it will not let me connect a plane old line to the open end points to close the loop. 

secondly , if I try the ground plane thing I mentioned above, it will not let me close the loop to a line other then itself. 

any ideas? Thank you so much for your help! 

[davebYYPCU]

Sorry about the late pics in previous post, but you lost me all the same, 

does this help?  Shape of the body becomes insignificant.

you have a mesh body, you need 50mm high plates sectioned through it.

You Mesh Section a sketch at each 50mm of the height of the body.  You said you sliced the back off, which should become ground plane, Right?

Each sketch is a job on the router.

While I don't need to do this, I figured if you modified the 3d printer to a larger enough table, put a mesh body on it (sliced face) and let it slice at 50mm layer height.  Closed loop on each layer, right?

Dissect the G code to one layer per file, you would be where you need to be with out mesh manipulation or sketch manipulation, but I digress.

Might help.....

[RScott9399]

So I have the mesh sketch and im editing it. Im trying to close the sketch. I click edit sketch and then under create match sketch curves. Im selecting the line tool and its letting me make this line across it. 

That is all well in good but I still cant extrude it because the sketch for some reason is not letting the line im making close the shape and become part of the completed sketch

I don't get it 

As you can see the line stays blue instead of becoming part of the sketch and making it brown

[RScott9399]

ok, I think I figured it out. You cant join the mesh sketch. You have to create a regular sketch around it. I see, Then I was able to base point. Hmmm ok getting there! Thank you! 

[davebYYPCU]

Yes this mesh extracting to sketches is convoluted - why any closed Mesh Section is not usable or converted to a profile is bewildering.

Mesh Section is an underlying set of read only articles traced from the body.  Has an eyeball.  Hide it and you will see the main sketch is empty.  The sketch that owns that Mesh Section remains empty until you add, create or fit curves to the traceable articles, and that happens when you Edit the main part of the sketch.

So you need a "traced" profile from that read only orange line, in the normal sketch, with dowel holes and datum points as per normal sketching, blue and black lines.  Similar to tracing a canvass only different.

Still not worked out what this

Then I was able to base point

means 

[jeff_strater]

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@davebYYPCU wrote:

Yes this mesh extracting to sketches is convoluted - why any closed Mesh Section is not usable or converted to a profile is bewildering.

---

The reason why a closed mesh section is not converted to a profile is kind of a guard rail to prevent you from creating really bad geometry.  If you think about the intersection of a plane with a faceted mesh, it is composed of a LOT of very small line segments.  Each triangular facet in a mesh, when intersected with a plane produces one tiny line segment.  If you were to extrude a profile made of very tiny line segments, each one would generate a separate face, resulting in a very heavy, and difficult solid body to work with.  By forcing you to re-fit the curves, you can dramatically reduce the number of curves in your profile, and thereby the number of faces in the resulting solid.

BTW, this is similar to the problem that we often see with imported SVG output from some popular graphic design software packages - thousands of very tiny line segments, especially from the "free-hand sketch" tools within those products.  Unfortunately, there are no such guard rails for imported SVG.  I wish there were...

[davebYYPCU]

(Mate, we know it’s not personal - directed at the System)

My point is that AD give us Fit curves to section tools, using them should be a background process, not an uneditable SVG, given that we created the section as required.  

Best fit spline, longest single line, arcs etc.  

I understand canvasses have no geometry, but these sections have snapable points.  

Fusion is doing faces in Mesh to Solid, profile detection with Project > Intersect - body, on request, so yes

manually doable - this example 5 lines, 3 Splines, for half before Mirror body,

but still convoluted.

[jeff_strater]

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@davebYYPCU wrote:

Fusion is doing faces in Mesh to Solid, profile detection with Project > Intersect - body, on request, so yes

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That's another one I would block, if I ran the zoo...  One of the bigger mistakes, IMO, that we ever allowed.  Converting a faceted mesh to a BRep, with one BRep face per mesh facet, almost always produces unusable models.  And, this often sends new users down a wrong path.  There are limited workflows where this is useful, but, again IMO, they are very limited...

[davebYYPCU]

Sorry,  I meant the excellent prismatic version, Mesh to solid, not the other type.

[trace_public]

For me, it seems that just remodel over your mesh, using solid modelling, would be the best solution. You can classically do Control Point Spline 3D sketches, using your mesh as reference, and you will get high quality solid model. I did this CRX that way. It does have a lot of meshes still, but most of bodywork is solid

[RScott9399]

I would of liked to try this, Do you have any examples or videos you can point me to try this? I would really like a solid model if for nothing else just to keep. I really hate working with meshes. Thanks for everyones help. 

[trace_public]

There's a lot of that video tuts over internet. This one as example. Just use your mesh as reference instead of three canvases

[TrippyLighting]

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@trace_public wrote:

There's a lot of that video tuts over internet. This one as example. Just use your mesh as reference instead of three canvases

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For even halfway dimensionally accurate reproduction of a scanned mesh, I would not recommend that workflowThe The method in your earlier post - using 3 and 5-degree control point splines is much more precise.

[trace_public]

That video was just an example. Before I wrote exactly about control point splines routine