Fusion 360 basic advice needed please

[Allan Bennett]

I'm making myself familiar with Fusion 360 (free, not for commercial use, version) in anticipation of Santa bring me an Ender 3.  I've managed to design a simple U-shape bracket to mount a GPS module on my heli, and am now trying a siamesed pair of truncated cones for another model.  What I'm unable to figure out is how to delete the overlapping bit at the junction, other than physically cutting/filing it off after printing 😵

 

The steps I used to get this far are (1) create a sketch of a trapezium representing a half cross-section, (2) revolve it to make a truncated cone, (3) shell the cone to leave only the 2mm outside surface, (3) copy the shelled cone, (4) drag the copy so that it overlaps the original, (4) then combine the two cones.  The 'combine' function suggests that there are 3 ways of combining -- join, cut, or intersect -- but I tried all three and none removed the overlap.  Looking at the online manual I see they mention a 'trim' function which I'm guessing might be userul, but it doesn't appear in my drop-down 'modify' menu.  Any advice would be welcome please.

 

[FlyinFlynn]

While others who actually have Fusion360 think about it, is there a 'tweak' function in Fusion 360?.. that works in 3D Design - it's predecessor.. select each outer side in turn and tweak it towards the centreline.

[Roger Adams]

1. Construct a plane running vertically near the middle of one of the cones. Do this from the construction menu, and use the offset plane option.

 

2. create a sketch on the new plane.

 

3. Project the edge created by the intersection of the cones. Choose the edge that is not visible in your view above. This will produce a parabola shape in your sketch.

 

4. add a line joining the ends of the parabola to create a profile and finish the sketch.

 

5. extrude the profile far enough to form a solid through the intersection of the two cones.

 

6. Use the combine tool, selecting the cut option, using the new solid to cut the cones.

 

there are numerous ways to accomplish this.  But this is the easiest way I could think to describe. Although it sounds long and convoluted it is all straight forward. 
 

Roger

[Allan Bennett]

Thank you to both of you.

 

FlyinFinn, I can't find any 'Tweak' command in my menus.

 

Roger, yes it does sound complex, but I'll try to follow your narrative.

[Martin Gay]

Alan,

 

I think you should be able to do a cut. This will make the "extra bits" into a new body which you can hide or delete.

 

Martin.

Edited December 19, 2022 by Martin Gay

[Allan Bennett]

Martin, I can't find a 'cut' command either 😒  I'll be trying Roger's suggestion this evening.

[Martin Gay]

Allan,

It is one of the functions of the combine command.

Martin.

[Martin Gay]

You could always paste the f3d file to the forum and one of the experts can have a play and let you know how they did it!

[Roger Adams]

I’ve just tried the method I suggested and although it basically works the result is not exactly as you or I would wish. Having reread how you got to this point the following does work.

 

Go back to when you had a single cone. (Before the copy and move)

 

Create a new sketch on the same plane as your original trapezium. This sketch contains a single rectangle that covers the portion of the cone that will overlap the second cone. The size is not critical so long as is big enough, oversize is good.

 

Extrude the rectangle symmetrically to cut away all of the unwanted portion of the cone.  The extrude tool should automatically assume the cut mode and will show the cut portion in red until you press the ok. If you have not ticked the box to keep the tool the block formed by extruding the rectangle will be discarded.

 

Now use the mirror tool. Select the cone as the object to be mirrored, then select the cut face created by the previous extrude as the mirror plane. Ensure the operation is join and press ok. 

[Martin Gay]

Roger,

 

Good Idea. As always there is more than one way to do this sort of thing in Fusion.

 

Martin.

[Allan Bennett]

Cracked it!

 

Thank you so much.  I followed Roger's instructions but for a moment got stuck at the last paragraph because I couldn't find any 'mirror' option in the move/copy submenu.  But I found that after I'd specified the distance to move/copy, the copy had X, Y, and Z axes superimposed on it, one of which I was able to 'grab' and rotate the copy by 180 degrees.  I then combined the result.

 

So one more skill learned, but so many to go . . . . 

[Roger Adams]

The mirror feature is on the create menu, the menu also contains the revolve feature that you used to create the cone. 
 

A useful feature to know is the ‘s’ key. Typing an s will bring up a dialog box. Then typing the first couple of characters of the feature/command you are looking for will give a list of available features that you can select directly. Can be easier than searching the menus. Enjoy your fusion experience.

 

Roger

[Martin Gay]

Every time I use Fusion, I learn something new. 

[Allan Bennett]

Thank you again Roger.  I realised later that the rotation that I used in the final step only worked because my object is symmetrical.  Your tip about the 's' key is a very useful one to know.

[FlyinFlynn]

11 minutes ago, Martin Gay said:

Every time I use Fusion, I learn something new. 

That's what I found... the problem  I found was there is so much to get through before I was able to produce anything of value, especially when I already have the basics in 3d design. For sure, fusion is much more sophisticated and professional, ( not to mention current!) but it is also much more complicated.

After thinking about it a bit, a procedure like the one Roger Adams suggests would also work in 3d design using the sketch rectangle  to cut into the trapizoid solid at the right place, delete the offcut and then mirror the remaining solid on the cut line... Like Microsoft products, there are many ways to get to where you want to be. 

[Allan Bennett]

I'm really chuffed!

 

I assembled the Ender 3 yesterday evening, re-assembled it correctly this afternoon 🤔, then printed off the little dog statuette that's on the SD card that came with it.  The quality is much better than that of other 3D-printed things I've bought on the internet, presumably something to do with the slicing settings.  The supplied PLA was just enough for the dog -- less than 1cm left sticking out of the feeder.