How to Properly Sketch/Design in Fusion 360 (some basics) - boat hull example

[Anonymous]

This thread will be used by poster and CADWhisperer to guide me in designing a small craft hull the correct sketch/design way. CADWhisperer, you are correct, I was trying to eyeball geometry using the grid lines.

Here is where I am so far after valuable basic sketch design input from CAD Whisperer:

[Beyondforce]

Hey @Anonymous ,

I'm not quite sure what is it you are trying to do. I opened the file and there wasn't much to see.

In case you want to create a boat hull, then you should check out these videos: https://www.youtube.com/playlist?list=PLjGKAi--ZCobt6eBTiT9ahIawIK4WQjqh 

[TheCADWhisperer · Accepted solution]

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@Beyondforce wrote:

I opened the file and there wasn't much to see.

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@Beyondforce I suggested that he post after each and every sketch, rather than building the Titanic - and the - asking why it won't float.

@Anonymous 

1. Your construction line transom width sketch is not fully defined (Note: No lock symbol in browser).

I would create a vertically constrained construction line from the Midpoint to the Origin and then dimension the vertical height.

2. ... construction line cavity radius sketch appears to have been moved off of sketch plane - don't do that.

3. stern sketch - use Equal (=) constraints rather than duplicating dimensions.

4. Sketch curved transom - good.

5. construction line 4ft bow - see #1  (even if the 48 is the only critical dimension - get into the habit of fully defining everything).

6. Notice the white endpoints on hull walls sketch.  Try dragging the lines. What behavior do you observe?

Add coincident constraints between the logical endpoints and stern sketch.

@Beyondforce 

Actually, there was a lot to see.  

Can you imagine where this was going if OP waited till the boat was done to start asking questions why things were falling apart as he edited the design?

[Beyondforce]

I look forward to seeing the end results and learn a new technique 😊

[Anonymous]

Sketches updated to all points mentioned, and posted below. In a day or two I will advance my design then post my next iteration:

[Anonymous]

@TheCADWhispereras you can see on the attached file (sketch 'hull walls top'), I cannot get the curved bow lines to become fully constrained even when I use the Fix constraint. And I do not know how to dimension the curved bow lines and maybe that is the problem. FYI, I made one curved line first then mirrored it.

[TheCADWhisperer]

Did you Project or Move those splines from a different sketch plane? 

Why are they green rather than blue?

[Anonymous]

@TheCADWhisperer  "Did you Project or Move those splines from a different sketch plane?"

@Anonymous  I cannot recall so I deleted them and recreated them in the attached file.

@TheCADWhisperer  "Why are they green rather than blue?"

@Anonymous  They are green because in my version the lines turn green when user constrains them as Fixed. I Unfixed them in the file attached and the lines are now blue.

[Anonymous]

I re-sketched the splines using Control Point Spline but still am unable to fully constrain the sketch. File attached.

[Anonymous]

I got it! I have a fully constrained bow now.

Back to me to continue working on my design.

[Anonymous]

@TheCADWhisperer I tried using Loft to fill the hull so I could shell it later however I was only able to Loft the first two layers together (file attached). The remaining two sections (between three layers) below the successful Loft remains unlofted. Any ideas why this is occurring? FYI, each hull wall layer (sketch) is fully defined.

[Anonymous]

@TheCADWhisperercancel my last post as I solved the Loft problem. The bottom profile had two openings that I have since closed which immediately completed the Loft and filled the hull as desired.

[TheCADWhisperer]

In the other sketches you have either an open end (no closed profile) or you did not convert projected geometry (like centerline) to Construction type geometry.  
See Attached.

And shouldn't this be curved back?  I think you made three of the sketches too long.

[Anonymous]

You are correct. I was so excited that the Loft worked at all that I did not notice that it did not work as planned. I will take a look at this.

[Anonymous]

@TheCADWhisperer  There she be! Final shelled craft is attached.