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Complete Lure Design Course – Designing the Lure Body

Complete Lure Design Course - Designing the Lure Body 1

All right guys we’re here at part two of the lure design and Fusion 360 crash course. Today I’m going to show you the power of using parameters and the loft command to sketch out a basic shape or a fishing lure that you can then manipulate easily moving forward. Let’s jump into Fusion 360.

So what I want to make today is a twitch bait because I don’t have one currently in my arsenal and it’s about to be super twitch bait season along the Texas Gulf Coast. I always like to save before I get started because it makes things easier moving forward. Now, I mentioned before about using parameters and logging parameters around the measurements of your lure and that’s super important. So before I even start drawing or sketching in Fusion 360, I’m going to click this modify parameters button and I’m going to out in all of those measurements that I talked about in the previous video. Those measurements are length, width, max width, point max, height point, nose dimensions and tail dimensions. That way, if I need to change anything or if I don’t like the width, I can just go in and modify these parameters and the entire model will update which is super cool.

Setting Initial Parameters

So I click on modify and change parameters and I don’t have any parameters in here yet because we’re just starting. Using parameters is what we want so I just click add and the first one we’re going to start with is lure link. Now, where you get these from- you can measure an actual lure, you could have a sketch or someone can tell you the measurements they want. So I want a 110 millimeter lure length to start with at least and we can change these later. A side note when you ever see like Yozuri Minnows or anything overseas, they have a number next to the lure. That’s usually linked in millimeters. For example, this is the sixth sense wake 80 which is 80 millimeters long.

So we got our lure length here and I want my nose width to be in the neighborhood of about 9 millimeters. Nose height is next and it’s about 10.2. You do the same for the tail and I’m actually going to do something a little bit different on the tail, I’m going to go to tail height and I’m going to put my tail height in as 9.25. Then for our tail width, this is where some of the real coolness in parameters goes in, I’m actually going to use the tail height and I want to basically make this 90 percent of the tail height. So I’m going to do multiplication and to do that in Fusion 360 I’m going to put an asterisk and .90. You can see here that number of the value is actually what I’m calculating so .90 is 90 percent of the tail height. Now if I came back later and wanted to make my tail a different size I can do that. Let’s say my tail is too big and I want to make it 9 millimeters straight, then my tail height automatically will adjust and so I’m just keeping the same ratio by doing it this way and you don’t have to go and update a bunch of numbers because they’re all driven off a set of numbers.

Complete Lure Design Course - Designing the Lure Body 2

Now we want to figure out what our max height of this lure is going to be. I’m going to start out at 30 millimeters which, again, is not set in stone, these are just to give you some kind of baseline starting numbers. The power of the parameters is we can go in and change them whenever we want but you want to get it within the relative range so you don’t have to double these numbers later. My width is 18.3, that’s the max width we run into here. So you can get by with just these measurements, but a couple of others that I’d like to have is the distance from the nose that the mac height and the max width occur at. So if you’re looking at this lure here, look for where it gets the highest in relationship to the nose and where it gets widest in relationship to the nose. That’s really going to influence this slope as well as this slope here and so by putting those in parameters we can change them easily moving forward.

So first let’s do the max height distance and that’s going to be 35. Then, you guessed it, the max width distance and this one I probably want to drive off of my max height distance because I don’t want those things crossing over right now. So when you start your max height in front of your max width and then at some point it moves back then you don’t want to make this relationship. But generally speaking, most of the lure designs I see, you want to make this relationship. So we’re going to take our max height distance and we’re going to add 5 millimeters to that and you can see it updates there to 40 since 35 plus 5 is 40.

Creating the Nose Cross-Section

Now let’s put these into action. So the first thing I’m going to do is create a sketch on this front plane. So I get in here and just draw a line and I use my nose height parameter and hit enter. I want to make sure that’s on my center line so I click a couple of things and my midpoint constraint and put that on that line. So there is basically the inside half of the nose. So now what we’re going to do is we’re going to draw another line that is my nose width. So we’re just going to click that there, we’re going to do nose width. Now the way we’ve written this is that’s going to be the full width so I want half of it so I divide by 2.Now, you could have divided by 2 when you put the parameters in, but I like to do it this way in case for some reason I need to go to a full width lure design, I can just use those parameters straight up. I like to use kind of flat sided twitch baits which a little bit of an angle on them, so let’s do that right now. This is another place that I could have used a parameter instead so I’ll actually go back and add one. I’m going to go back up to modify and change parameters. So I’m going to hop back in here and add a user parameter which is going to be my body angle. This angle degree is going to be 100 because it should be if I’m drawing a straight up and down line. The line I’m making I want to be a construction line because it’s not part of the actual design, it’s literally just holding my space value out there.

Complete Lure Design Course - Designing the Lure Body 3

So now I’m going to draw another line, a real line, here and I want this to be the nose height. I’m going to go times .65 so 65 percent of the height and then I’m going to use that body angle to be my angle and hit enter. Now we’re floating and I want to midpoint this to here and we’re dimensioned pretty well. Now I’m going to raw a fit point spline which is you can get away with an arc would be better but I’ve done this about nine times already and I can’t get an arc to work so we’re going to use a fit point instead. I’m going to draw two of them and the reason fit point splines are not the best this to use is that you have to add a lot of dimensions to the to get them to solve. So the first thing I want to do is I want this arc up here to come out straight so I get it close to the horizontal and then put a horizontal vertical straight on. Then this guy I want to actually line up with this line so I’m going to drag my horizontal over straight and drag him. He’ll actually snap right there and then I’ll shrink him down a bit so he has this parallel constraint on this line. If I’m happy with that, I need to hit the D key and dimension these guys here. Because I’m super nerdy, I always try to make them a rounder number. Once you have the angle of these handles and all of them dimensioned, your sketch will become properly constrained. So now we need to do the same thing down here on this but we don’t need to watch that, we’ll bring it into the next sketch.

Creating the Midpoint Cross-Section

So we got our nose and it’s going to be the same process moving forward that we just did except for three different steps. I’m going to skip the max width, I’m going to assume that the max width point and the max height are the same. So we’re going to draw the middle of our lure now, basically the max height point and the max width point. We’re going to say they’re the same here so I’m going to create a new construction plan, an offset plane from this front plane, and we’re going to use our max height distance to create this plane. Then it pumps back to 35. We’re going to right click and create sketch, we’re going to turn off this other sketch because we don’t need it right now. We’re going to create another line, this is my max height. I’m going to midpoint again to there and now we have our max width that we’re going to create another line. This is going to be a construction line because I don’t actually need it to be a real line. I’m going to use my max width and again divide by 2. We want to make sure this line is straight. I’m going to draw a line, and again, I’m going to make this one max height and I’m going to times .65 again, 65 percent, and this is going to be my body angle and hit enter and I’m done.

Complete Lure Design Course - Designing the Lure Body 4

I’m going to midpoint this guy here on this, that’s going to keep it the right distance away and I’m going to hit escape and add my fit point splines. Again, now I kind of already mentioned this before, fit point with splines are super fiddly, so you want to have the least amount of spline points that you can get away with here. I think we get away with two, and again, process is the same as we’re going to take this guy and we want him to come straight out. We’re going to put a horizontal vertical constraint and we’re going to pop this guy into a tangency there and we need to shrink him down just a little bit. Same thing here, make sure he’s horizontally vertical constrained in this guy we’re going to tangent constraint and make him a little shorter. Then all I need to do is go around and dimension these guys and make them pretty numbers.


Creating the Tail Cross-Section

Now we’re on to the next part which is, you guessed it, the tail. So we’re going to create another construction plane off this front plane and we’re going to use our lure length parameter. So now we have a plane that is exactly as long as our lure is going to be that we’re going to create a sketch on. I’m going to speed up through this guys because I’m really just going to use the parameters for the tail height and tail width which is the exact same thing I did in the first two lines. Just remember to divide by 2 and a quick note here- I didn’t give my tail an angle because I like to have a lot of meat on the lure because that’s probably where I’m going to hook the most fish and thus where I want to give the most material. Quick point on that spline, you saw the ones on the outside since my lines are vertical. Now, I had to really shrink down the circumference of that bend and made a really tight curve there to make it even.


Creating the Profile of the Lure

I turn back on all my other sketches and you see I have an outline of a lure here. There’s one more thing I have to do before we actually create the body which is the side profile. Now most twitch baits are kind of this meridian here where you can see it has a nice curve across the top, but the bottom kind of jets in right here. Now, I can measure that but I’m just going to fiddle with it. So in order to do that we need to draw rails for our loft here. So the key to rails is hey have to touch all of the profiles in your loft. So we have these three profiles here and I need to make sure they touch. The best way to do that, I find, is to use the project intersect command and what that does is projects into this sketch all the points where those profiles actually cross that sketch plane. So basically, it makes it easy to snap to it. I’m going to go back to my old friend fit point spline and you can see if I come in here and zoom in, there is that project point. I can kind of double check by turning sideways a little here and clicking. As long as I don’t change anything it’s going to stay fully dimensioned.

Complete Lure Design Course - Designing the Lure Body 5

Now we go to the next one, click here, click here and click here. You get basically the same shape. I often see people trying to put a point in right here but you don’t really need one and it’s going to frustrate you later. I’m going to hit the escape key and I’m just going to come back here and grab this handle and pull it straight up and out. I might be able to get away with a horizontal vertical constraint on it. I have that constrained, this one is not constrained so now I have to go in and add all the dimensions to these guys. I need to add all of the angles and this is where things get not so fun. Because for some reason this can be a super fiddly process, I don’t have to type anything I just hit enter and now I’m fully dimensioned because everything has an angle. This one’s horizontal vertical has a dimension so we’re all good.

Using the Loft Command

So let’s finish the sketch, what you’ve been waiting for. So we’re going to go in and create a loft. Now we have profiles up here and I can just start clicking my front, middle and back. Now, you can see by default we get a pretty boring shape. Now one thing I’m going to show you really quick is something that we’re not going to use but what I find pretty useful is usually a pretty good way to rough in a lure. On the back of this right profile number three, if I can change it to direction it kind of necks it down. There are different curve profiles and I can grab this and I can move it and it can neck down a little more. All this is doing is determining where the second profile, which is in the middle, and the third profile where they started. So if I move this further away, I’m reducing the amount of influence the middle sketch has. If you’re going to do a completely even lure this can get you pretty close to that classic fish shape.


The Power of Parameters

But what happens when I do rails, I come down here and I click my top rail and my bottom rail and now I have the exact same shape I want. Now don’t worry about these sharp edges in front here, we’re going to add fillets to them. What I really want to show you is now we can manipulate this lure design just using those parameters. So we’re going to come to the right and I’m going to click modify- change parameters. So here in my box I’m going to make it a bit smaller and say I decide I want to make this thing 90 millimeters long. I can come in here and change it to 90. Same thing if I wanted to make it 135 millimeters long, I would just enter 135. Now you can see what happens is all of my proportions stay the same and the location of my nose, and more importantly, my max height point or max height distance. I think there’s a formula that you could get into where you base your max height distance on the overall length but for now let’s put this back to 110. You can mess with these numbers until you have your lure the way you want it, you can make all these changes and the computer will do the math for you.


Hey guys, that’s it for this lesson. We’re obviously going to keep working on this twitch bait moving forward. If it’s not clear to you already, we’re going to design only one half of this and then we’re going to use the mirror command to just make a copy of the half. That way, we literally do half of the work.


Take Care- Tight Lines