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Ben752

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  1. www.rdgtools.co.uk sells Titebond. Sadly, B@Q has mimicked Home Depot in the states and hardly carries anything useful or of quality.
  2. "a pile of patches" was actually pretty accurate in that it was constructed with several tangent arcs. I had a similar experience of feeling it was just not right -- and that a different technique was needed. Fusion 360 has curvature combs, draft analysis and curvature map analysis features. Here is a curvature map analysis I ran, I haven't been able to to see much except when using the min/max settings and cranking the max values way up. Hopefully this is a good thing (my prior hull showed more variance). The CVs close together are a byproduct of using a mathematical fitting technique. Fusion using fixed spacing for knot placement of curves. While I'm not NURBS expert from the match side, my understanding is that if you are using uniform knots then you would need two CVs close together for it to generate the curves. Now whether they should be split vertically like that, my guess is probably not. I did run the fitting routine several times and it tended to favor placing them like that. While i'm not totally satisfied with it, i'm trying to remind myself that I aught to start working on other areas and come back to it later. When I intersected a plane with the hull the pattern for a frame seemed to match up well against other resources I have so hopefully that's a positive side.
  3. That was my thinking! My own inability to be happy with moving the CVs (i'd never be happy enough) led to me searching for a different solution. I ended up using the Python library scipy as it has the relevant spline objects in scipy.interpolate and I used the differential evolution algorithm as the solver.
  4. That is correct. It took quite a few tries to figure out exactly how AutoDesk implemented the spline knots (they actually confirmed it in a support request in their forums). In the first screenshot above, I used measurements at each station line and it gave me the output of the 7 control vertices (with the first and last being the corresponding points I provided).
  5. Hi everyone, I wanted to give an update on my progress. Normal life stuff has been busy since the last post. My company was acquired, subsequent expansion of our office here in the U.K., met a nice English girl and more focus on my U.S. Brig Niagara. All sorts of great things. Anyways, enough about that. As I was progressing through later parts of drafting, I came to realize I wasn't really happy with how some of the lines were formed. Also, AutoDesk launched CV splines for Fusion 360! I ended up starting a starting over my 3d model to incorporate lessons learned about Fusion and feedback from ya'll. Also, I stopped straddling the fence on how much to use from the TFFM plans and the original drafts -- I've decided to go using the original references almost exclusively. In this second start, I've switched to the following techniques in fusion: Using CV splines for the body plan and striving to keep the same number of control vertices Defining key curves using CV splines that are fit using numerical optimization methods. This last part took some R&D (I work in technology and spend a bit of time doing data science/AI type solutions). Below is an example of what I've done relating to this. I started by taking measurements off the drafts and correlating them across plans. This yields points to fit, one challenging is that fitting CV Splines isn't a common practice. This is partly because they are parametric which to my knowledge doesn't have an analytical solution. What I did was use a genetic algorithm to solve for solutions that are very close using the points that match above. The result seems to be a more smoother fit that is much closer to real curve than I could manage moving points around. FWIW, there are a few naval architecture research papers that describe this technique. Below is an example of a breadth curve fit to the measurements. One interesting consequence of this is that it yields a fully constrained sketch in Fusion. It seems that splines also tend to work better when lofting. I think overall it's a much nicer fit than the previous technique I used.
  6. Does anyone happen to know the specs on the DC power supply for the DRO box?
  7. Finally the new model workshop setup after my move to Edinburgh, Scotland. There is a rather impressive hobby store called Wonderland Models just walking distance from my flat. I found this squadron green putty a good substitute for the bondo spot putty. I laid out the deck in a similar manner to xken, and used dark Titebond II along with some black grey to mimc the caulking. I then used my miniature veritas bench plane to remove the excess and borrowed a piece of glass from my furnished flat to create a flat surface to plane on. Later I ghosted the plank ends using a mechanism pencil, a compass to create a pattern to trim the deck. Last evening, I started laying out the plank belts using thread.
  8. Steel files are the way to go, diamond impregnated ones seem to cut too fine for wood. After buying cheap ones and then later purchasing some Vallorbe needle files (I think Grobet USA is the same company), I can say it’s one of the best purchases I’ve made. https://contenti.com/jewelers-metal-files http://www.ottofrei.com/jewelry-tools-equipment/bench-tools/files If you want to hog lots of wood, woodcraft has some great needle rasps.
  9. Turns out they just launched CV splines (control vertices), https://www.autodesk.com/products/fusion-360/blog/july-26-2018-product-update-whats-new/
  10. One of the limitations of fusion is that the spline support is far from great compared to others out there. They should be launching proper CV curves within the next year or so. They have recently published a post showing some of the upcoming capability, which should put them more inline with that of solidworks.
  11. This is great info. I've was going back and forth of using two different radii on this. Seeing this confirms it's possible that might be the case.
  12. Thank you druxey. I revisited the the sternpost and found that the roughly matching the rate of concave curvature inward on the the half breadth plan suggests the head would be approximately where you said it should be. Reconciling the different plans and sources certainly adds a wrinkle to selecting the right path when they don't appear to agree!
  13. After a few transatlantic flights, I've managed to the roughly sketch body plan across the relevant planes set along station lines. I ended up going back to the patch workspace instead of t-splines as the ability to edit edit and adjust far out-weights the smoothing ability. I've ended up using projected points from the relevant half-breadth and sheer sketches combined with construction lines to establish bounds of the geometry. Unfortunately it looks a little noisy in the screen capture. I tried using splines but quickly became frustrated and went back to using arcs and tangent constraints. Originally I used 4-5 arc segments for some but once I discovered the zebra analysis and repeatedly adjusted the curves for fairness, it became apparent that as few arcs as possible will result in improved fairness. While still can be improved, if I keep continuing at this point i'll be spinning my wheels until I'm able to model other areas. Which brings me to how to bridge the stern post, station 20 up through the wing transom. I created construction planes using the sheer plan for the bottom of the wing transom, transom #1 - #4, and one in between the keel and the bottom of #4. I then created sketches on these planes. This adds some complexity as projections will be skewed when looking down towards the top of the keel. I added the various reference points and intersected the stern post at each sketch. However, a rough sketch of the filling transoms (?) profiles appear way off from the TFFM half breadth plans. I've struggled making the 15" square at head of the stern post fit the rest of the plans. TFFM states 1' 3" on pg. 41, pg. 64. However, the plans seem to agree with about 12". Additionally, the contract I have for the Hornet states: "The stern post to be of good wound? oak tim of the best kind free from defects. sq. at head 12 1/2 (which is t run up to bolt in the Lua? deck beam)" Which leads credence to the ~12" dimension. Does anyone have thoughts on regarding this? This screen shot is taken top down which means the profile lines for the filling transoms are project per the angle of they're drawn on.
  14. Thank you for pointing this out. I plan to go back and alter them but wanted to keep it simple as I work through the various components.
  15. When I initially started this project, I started down the path creating a 3d model in Fusion following the order of the book. It quickly became apparent that this strategy is not an optimal way of working. However, the work below on the keel is fairly simple and was able to be salvaged before I shited to following a construction order closer to what is described in Steel. The process used is as follows: 1. Under a new component create separate sketches for the fore, aft and a middle timber of the keel. 2. The top plane worked well to construct the aft and middle sketches as it lends itself well to a extrude along the Y axis. Because the mid keel components are repeated, I repeated the component using the rectangular pattern feature. This gives me a reference edge to project in the fore timber sketch with the added bonus of propagating tweaks forward. 3. On the fore timber, I constructed the sketch using the left side plane as it allows for projecting the arcs of the stem to model the the boxing. Whenever possible, I"ve used projections off of one of my "master" sketches to allow for propagation of changes to the bodies that model the timbers. 4. To create the simplified boxing joint I created the sketch for the lower stem on the left plane, extruded on one face left face to 1/2 the thickness and used the combine/cut option on the fore keel. Then did the same on the other side but make the fore keel the cutting tool.

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