[adamchapman]

Hi,

I've designed a wind turbine blade with some aerodynamics code I wrote in Matlab, and saved the blade geometry as .txt with format:

x1 y1 z1
x2 y2 z2
... ... ...
xn yn zn


I can open this in mastercam and it looks like a nice point cloud.

This is great, but now I need to turn the point cloud into a solid or a surface before I can make machine toolpaths.

What can I do to turn my point cloud into something machinable?

[kojack]

Hi,

I've designed a wind turbine blade with some aerodynamics code I wrote in Matlab, and saved the blade geometry as .txt with format:

x1 y1 z1
x2 y2 z2
... ... ...
xn yn zn


I can open this in mastercam and it looks like a nice point cloud.

This is great, but now I need to turn the point cloud into a solid or a surface before I can make machine toolpaths.

What can I do to turn my point cloud into something machinable?

give me a few Hrs I can convert it to you ...

its kind of a pain in the butt ...

basiccally have to mesh it and turn it into a STL file ...

I do it all the time

[adamchapman]

Thanks very much for the offer but I really need to know how to do it for myself; the aerodynamics isn't perfect yet so Im expecting the blade design to change a few times before im happy with it.

[adamchapman]

OK I've actually made an STL file out of my matlab coordinates now.

How do you turn the stl mesh into a surface? surely you dont have to individually highlight every line with
create -> surface -> net surface

[kojack]

OK I've actually made an STL file out of my matlab coordinates now.

How do you turn the stl mesh into a surface? surely you dont have to individually highlight every line with
create -> surface -> net surface

looking @ your file you dont need to make STL or mesh ..

you need to draw some closed poly lines and draw some surfaces

[adamchapman]

Wouldn't that require drawing splines round all the cross sections? This will be particularly time consuming when all the cross sections are not identical

It seems very time consuming, is there a faster way using wireframe toolpaths? I suppose there are also problems with sensing the upper and lower side, as I only have a 3 axis cnc. Hence I would need 2 toolpaths, one for the top and one for the whole thing flipped to cut the underside

[cadcam]

Hear is a quick little demo of doing it in MC. about 3min run. this is a Windows Media file
http://www.mastercam-cadcam.com/vide...pointcloud.wmv

[kojack]

Hear is a quick little demo of doing it in MC. about 3min run. this is a Windows Media file
http://www.mastercam-cadcam.com/vide...pointcloud.wmv

nice video ....Nice selection of music also ....


I noticed on your model also there was some bubbling @ the End

I if you zoom in on your spline there probally all twisted on the edges

I had to explode the point cloud and manualy fix the ends ...

Definelty faster than Rhino ..

[kojack]

I know MC9 has create splines Manual and automatic

but I dont think it works like X3 ????

[adamchapman]

That video was cool. Thanks a lot!

I noticed the funny spline behaviour at the trailing edge too. There is probably a shorter distance from top to bottom than between neighbouring profile pointsd. I can probably fix it by getting Matlab to make points much closer together at the trailing edge.

Turbine is looking nice in solidworks now

Thanks again
Adam

[timmydabull]

that was bad arse Video CadCam i liked it a lot with the background music

[ObrienDave]

Having run into similar surface "folds" or "bubbling" before, I can tell you the problem does not lie with the number of points that make up the spline.
It has everything to do with which point you start each spline with, and the number of points in each curve set.
For example, lets say the middle of the flat area is at the origin of one axis.
In the video, lets say its the X axis.
If you pick the 10th Y+ point for spline 1, and the 8th Y+ point for spline 2, and the 6th point for spline 3, and so on, the starting edge for the resulting surface is NOT parallel to the curvature density of the points.
Follow me so far?
So, as the surface follows the spline around the curve, it tries to match each spline node for node.
It's like taking a cylindrical drinking straw and trying to twist one end around the axis of the straw and still trying to retain the cylindricity.
Ain't gonna happen.
I would make the surface the same way as the video except for one major difference.
I would zoom in on either the leading or trailing edge, for example, and make sure I picked the exact same point on each set, so the starting point of each spline was perpendicular to the point cloud.
It is also very important to make sure that each set of curve points have the same number of points.
That way, you get the same number of node points for each spline.
Therefore, you get a smoother surface.
If this doesn't make sense to anyone, please post a .txt file of the point data, and I will post an example to this thread.
(DOH! Just saw the txt file. example forth coming)
Good luck with your project!

[cadcam]

obriandave, you are correct on the fine detail to make for a better and cleaner surface.
that is why Ruled and loft are now grouped together as the logic works the same as you talked about.

As for the video as you can see I took the data given on this forum and made no changes just a basic coverage of how you would go at it.

PS seems like we have seen you around for awhile, How are you doing?

[ObrienDave]

Ok, here is what I'm trying to explain in MC9 format.
Levels 4 and 5 are a very small example of the twisting effect caused by not selecting the points in parallel to one axis.
I know the splines on level 4 have a funky curve at the trailing edge, but it does not affect my example.
A trick I used for levels 2 and 3 was to take your data and add a break between each set of curve data.
What that does is to force a different spline at each set of X axis data.
So, rather than importing the txt file as points, I used splines, hence level 2.
As you can see the resulting surface on level 3 is perfectly smooth with no twisting, and machinable.

[ObrienDave]

Cadcam,
Thank you for asking.
Since I gave up this life to become a long haul truck driver a year ago, my stress level from not having to deal with these kinds of problems, has dropped by about 99%.
I still have the gray hairs, but, the rapidity at which they appear has diminished.
I still, however, enjoy helping out when I can on the more advanced aspects of MasterCam.
There are enough really good people on this forum to help the younger ones with the simplier tasks.
I'll still be hanging around for a long time.
C YA

[kojack]

another way to fix the problem is not select all the splines when lofting

just do a few sections @ a time and you will see when it distorts and can select diff points on the loft

[adamchapman]

Thanks Dave,

So the break you mention is just an empty line in the text file. Nice and simple, perfect for me!

[cadcam]

long haul truck driver

Really. Dang we lost another god programmer. :-)

[ObrienDave]

Adam,
One of the things I learned to do was to present MasterCam with the minimal amount of information needed to accomplish the task.
A quick example is, you don't need vertical surfaces to machine a cavity, IF you use the "roll tool around all edges" option.
The less info you give it, the faster it can evaluate the cuts.
Of course, there are going to be times when that info will be needed.

Cadcam,
I still have a few people I help on the side.
So, you really haven't "lost" me.
I also don't consider myself a "god programmer", just slightly smarter than the average bear.
Thanks for that.