“@ReeceEngineering hopefully my posts are not seen as just being overly critical on your designs and techniques.”
Your posts have absolutely not been seen as overly critical! I am happy you all are on here helping me. Also I have pretty thick skin and I know that all my methods are not the best and that I have a lot to learn. The reason I began this project is to learn Fusion360 better as I have included it on my resume and I would like it to be an honest addition. Also because I was struggling to make an EDF Jet out of foam board for the past few years, I know my 3d printer is capable of some amazing things if they can only be designed.
“Lofting from a circular to a rectangular profile takes some forethought, if the sharp edges are to be filleted.”
I changed the profiles to rectangles after your suggestion that lofting filleted profiles isn’t a good idea. I just tried adding the fillets after lofting and its not possible. So I think we are stuck lofting the filled profiles for this one.
“As has been mentioned already, you've got to loose some of the profiles, or first make the rails and then size the profiles to match the rails.”
It looks like you are right about this. If this loft is going to be this dependent on rails then we really only need one rectangular profile towards the beginning. Truth be told the reason I began in such a fashion is that this is about the only way I knew how to control lofts in Inventor, hence the title here haha. Im glad to learn better and less time consuming methods.
“The screenshot shows the curvature your top rail and because you are determined to match I to the profiles, the curvature looks bad. IF you really need these areas of high curvature, then this loft should be broken down into several individual segments.”
The loft looks pretty ok in this area on the outside, fairly smooth and flowing surface should net a low C/D. Now if we break the loft down into several segments all running on common rails how will that change anything? Isnt it the rails that’s resulting in this high curvature?
“Also, if the geometry between the 2nd (from left) circle and the the first rectangle should be straight, then this segment should be a straight loft and actually would not need rails, but if you do use a rail, I should be a straight line, not a spline with curvature.”
Its looking pretty ok as is. Though we may end up moving that curvature farther back once we get to modeling the intakes. Take a look at the bottom of the Panavia Tornado to see the shape there. The designers of that jet used a really simple approach and I thought it would be a good element to apply here.
Now if we do use a straight line between these 2 sketchs wont that result in a ridge with each of the surronding lofts? What would be the cure for that?
“I am attempting to create a high quality surface. A quality that is unlikely to be discernible in a 3D printed model from a model with lesser quality.”
I like what I hear! This is something I would really like to learn how to do!
“One of the "problems" you'll observe in the end result is that I loose G2 surface continuity across the center line. I know what to do about it, it's fairly simple (those were his last words) , but I don't think that should even be the case.”
The model pictured here is looking pretty good and smooth. In that area where its loosing some continuity it seems like if it were smoothed out in either direction it would mean a larger and heavier model. So if its not a curvature issue that will cause a higher C/D then lets err on the side of minimum volume. That’s the reason Id had the guide rail curve rapidly to point at the final circle sketch.
“Anyway, here are some results. I'll keep working the model and post back something later.”
Thank you Peter
“I am attempting to avoid splitting that body to leave the two top and bottom center surfaces intact.”
By splitting the body do you mean altering it so that Fusion sees it as separate parts in a certain area? Why would we do that?
“SO I use the same object for splitting surfaces to create the same trims on the opposite side. Then I copy/mirror the surfaces to the other side attempting to stitch it all into one body.
What works on the original side, does not work on the opposite side. That means that the original solid was not symmetric! The gap between the surfaces is actually quite large!”
That’s quite odd as the only guide rails in the model that had been posted at that point in time were on the top and bottom. How could that possibly have lost symmetry?
Im also confused as to what you mean by splitting surfaces and creating trims. Are these methods of smoothing out the contours?
Im having a really difficult time analyzing whats going on in the workflow of the model you last posted as when I move the end point back through the steps the model disappears completely as early as even the first few lofts. Is this due to a later vs older version of Fusion360?
