Ski Builders Forum

i am fairly good at using SW my question is have any of you modeled your skis before you build them. i have built one and it looks okay i am having trouble because i mated the points of camber to make the symmetrical but the model goes crazy when i try and change the tip.

the sketch is made of 3 arcs which i have made tangent to each other any ideas would be great and very much appreciated

Why not use snocad for the initial drawing and then import the dxf to SW if you want?

the main reason is that you cannot do mixed camber skis also i am using the ski model to create the mold. and everything is in solid works

You can do mixed camber if you get creative. Basically you create 2 files instead of one. One for camber only and one for horizontal dims only. The print each profile separately. It is a bit more work but you dont hve to learn another program like solid works. To created the long rocker tip just increase the tip length by a lot and shorten your running length.

Sounds like you know what you are doing but I use SW and just connect the points with a spline for my rocker/camber profile. I know you are probably trying to get a perfect arc for the underfoot section using the arc but mine come out just fine.

skibum wrote:Sounds like you know what you are doing but I use SW and just connect the points with a spline for my rocker/camber profile. I know you are probably trying to get a perfect arc for the underfoot section using the arc but mine come out just fine.

I did it the same way. You should be able to accurately dimension the points in the spline to make it just how you want it. Then building it exactly like the model is whole new challenge. That's cool that Snocad is out there and works for some people, but don't waste your time if you got a SW license.

Just doing some more experimenting today I found I can draw a perimeter circle and trim the excess to give a smooth arc for camber (81m radius or so depending on length of course). When first draw it does not cross the points properly but when you trim it it snaps to where it should be. I will still use the splines to do the rockered sections. If you want to see one of my files let me know.

could u post a screen shot of your sketch. do you camber profile and then offest entities to get the sidewall height then extrude that. i have been trying to do it that way but i am struggling a little on how to get everything to work together.

Okay well the only part I extrude is my reverse mold for my cores. Everything else I keep in 2D. I cut everything out with my CNC. I don't know if you have access to one or plan to print things out and then cut them out. My advice is to keep things simple and keep it in 2D. I don't actually cut out the outline I have printed. I modify the shape to make my core outline and a separate file for my base material cut out (stepping in for the edges). Sorry for the terribly edited screen shots. I hope that helps a bit

Do not, in any way, incorporate Photoshop and SolidWorks. That shit does NOT work together...it sure looks like you're tryin'.

I cut everything out with my CNC

so jealous!
i do my drawing in autocad. i stick to arcs that meet at tangents for ski shape (much easier edge bending compared to splines that are constantly changing radius). i think using splines or ellipses for the rocker is good though as the gentler transition from a large radius to a tighter radius gives a more even press. on3p have gone to elliptical rocker this year. i think they're right that this type of rocker shape planes better in pow and allows better edge engagement, but it also makes the manufacturing of flat based skis more trouble free too ( in my opinion of course).

that helps sooo much i have been thinking about using a CNC mill to cut out a core template but i don't want to mill a couple hundred dollar out of AL before i try ride the ski and i am sure i like it.

thanks for the screen shot. do you own a cnc or work for a place with one. also are you anywhere near Denver CO?

do you think it would be a good idea to incorporate an elipse rocker into a mixed camer ski. i think that the transition would be hard to build in the mold but i am new to this so i might be totally wrong please let me know

@ falls: Well I just tried using what solid works calls a tangent arc and it works great. I have taught myself sw so I am sure I don't do things the most efficient ways possible. Thanks for the tip.

@ ggardner90: Yes I have my own CNC but I'm up in Canada. Yes doing a ellipse rockered ski would work fine in a ski. I find it a bit difficult to draw beacuse (from what I can see) you need to find where the centre of the circle will be. The transition is easy enough just decide where your rocker will start and put a point there (at y=0). I also use a "centre line" running horizontally at y=0 to help give a reference point when designing it.

@ Brazen: Thanks for the advice but I was only using it to do that terrible writing on my screen shots (I've never taken screen shots before)

Here is my method to create ski designs using Solidworks. Sketch relations are not displayed in these screen images. Use tangent and coincident relations as necessary to establish desired geometry.

This example reflects my latest ski build, an elliptical rockered ski 186cm long.

Parallel to RIGHT PLANE (= Ref plane = max camber), create additional planes for the tip and tail contact points and ski waist (center of side cut radius)


On FRONT PLANE:
Create the profile sketch, rocker ellipses and camber arc. Ellipses are tangent to the horizontal TOP PLANE and the camber arc is tangent to the ellipses. Camber height dimensioned from the top plane. This example design has low rockered tails:


Create the ski base profile sketch by converting and trimming the profile sketch:


Create a ski top profile sketch, an approximation used for press form design:


Create the press form sketch, offset curves from ski base and top profiles. Tangent arcs extend the ellipses at tip and tail. My concept is to create matching upper and lower press forms in order to maintain a very flat fire hose bladder which maximizes the contact patch. I do not use a cat track, just a few sheets of hardboard and plastic to help distribute pressure into the ski lay-up:


On TOP PLANE:
Create the side cut sketch, can be single or dual radii, or any shape you desire:


Create tip and tail spline shapes. Keep the spline simple, just three points, one at each end and one near the middle. Place an additional point on the spline and draw a horizontal construction line from it. Make this line tangent to the spline, this locates the point at the maximum distance from the ski centerline. Dimenson to this point to define the ski width:


Tail spline shape close-up view. Use the control polygons to push and pull the spline into desired shape. You can also drag the position of the middle spline point to modify the spline shape. Display the minimum radius to help determine shape. Also enable the inflection points display option to make sure you're not creating inflection points:


Create the ski shape sketch by converting and trimming side cut and tips sketches. Mirror to create the full ski outline:


Create the base P-tex shape by offsetting ski shape sketch by the width of the ski edge. This will be used for making the ski base template:


Create the tip fillers sketch by offsetting ski shape as desired:


Create the sidewall block sketch by offsetting ski shape as desired. I make a template for shaping the ski cores to prepare for sidewall block attachment:




The proceeding 2D sketches are then arranged on a drawing sheet and saved as a PDF file for plotting. I use a custom paper size 84” x 42” and I have access to a nice HP roll-feed plotter:


To create a 3D solid model of a ski, used to evaluate the overall ski shape and various graphic ideas, I found the following method works best.

Convert the ski base profile sketch and create a Surface Extrude feature:


Convert the ski shape sketch and use the Wrap feature to create true 3D ski shape geometry. The Wrap feature is used three times to achieve the whole ski (since the base profile is comprised of three segments):


Create a 3D sketch from the wrapped curves:


Delete outside faces and Surface-Knit the model together:


Use Insert-Boss-Thicken to create a solid model from the surface model. Then convert the ski top profile sketch (on the front plane) and use Cut-Extrude to create the proper ski thickness profile. To bevel the sidewalls use Cut-Sweep following a 3D sketch path that is converted from the lower edges of the ski model. The sweep profile sketch is drawn on a plane that is normal to the end of the 3D path sketch:


Apply colors and textures as desired. My logo is a 2D sketch wrapped onto the top face of the ski, then turned into a Split Line feature and colors applied to the faces. A photo of my graphic fabric was used as a Solidworks texture on the model. The steel ski edges are not modeled:


Check out my photo album to see these finished skis. My press forms, tip fillers, etcetera are also shown. Hit the www link.

Cheers,
S

Well hell Shif, you are WAY better with solidworks than I am! I'm going to try the insert boss thicken / cut-extrude command on my next core. I had just been setting points in a 2d sideview then extruding the pattern to represent the top of the core block. This looks like a much slicker way. Thanks for the beautiful post.