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Creating parts i VX from point cloud

    
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OldForumPost

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Message 1 of 15

 Creating parts i VX from point cloud
26-01-2007 05:10 . am   |   View his/her posts only
One of my customers wants to try the point cloud functionallity within VX.
Their parts are very small and have loads of sharp edges on them.
Does anybody have any examples that I could have please that are done with the VX code (not other software)

Next question.

For yet another customer I need to be able to split an existing stl file (in this case model soldiers). So that core and cavity parts can be milled.

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Kevin

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Message 2 of 15

26-01-2007 06:43 . am   |   View his/her posts only
Materialise Magics Tool software will do this...but then that won't help Mike :-)

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Kevin

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Message 3 of 15

26-01-2007 06:46 . am   |   View his/her posts only
If its any consolation Delcam last year had a feature on Games Workshop and how they used Powershape and PowerMill to machine out the tools for the intricate figures.....well I know the guy who does tech support/sales for SensAble and months before he showed me how Games Workshop made the figures and did all the tool core/cavities in the SensAble top end system :-)

Thats another system that can do it....but clearly Delcam can't (or couldn't).

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ChrisWard2k2

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Message 4 of 15

27-01-2007 09:03 . am   |   View his/her posts only
Hello Mike

Splitting STL files with a plane is of course any easy task with the VX Wizard designed for that job. So, do you have an example file and example non-planar split line that you need help with?

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OldForumPost

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Message 5 of 15

29-01-2007 03:41 . am   |   View his/her posts only
Hi Chris
Any stl shape will do, The example I have been working on is a bit big even when compressed. But you don't need that. Create a curvy shape that when you create a silhouette parting curve it's not planar. The one I used is a figurine that I got from Enrico. I can send this to your ftp site if you want but there's no need. Once you have created the curvy shape, export it to stl. You can then use this stl file to try and split it. The problems are, 1, how do I create the parting curves for the core / cavity, and 2. how do I split the part.

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ChrisWard2k2

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Message 6 of 15

29-01-2007 01:24 . pm   |   View his/her posts only
Hi again Mike


I should have been more specific with my question because the file does matter, as do the circumstances. The VX tools are not designed to work with STL data as though it where simply regular surface geometry. As you know, it is very often the case that a VX function can be persuaded to do something that it has not really been intended for. In the case of STL imports, and VX tessellations ("internal STL"), the capability is primarily there for viewing and construction around, rather than manipulation of. For example, you might be the designer of a component in the engine bay of a motor vehicle. VX can turn the point cloud scan of the surrounding structure/other existing components into tessellations, such that you have a representative, clearly defined space envelope for your part.

To work with STL data in order to produce a mould tool, it is necessary to convert it into surfaces. To do this, areas of points are partitioned and surfaced, building a "patchwork quilt" of surfaces to describe the finished part. The more critical the detail, the more surfaces required. Now this is where the type of shape and amount of detail (and critical tolerances) really counts. For just a one-off, you can always rely on getting a good result with VX, but it could require some hard work to get there. Another factor here is the User - some people like yourself have an eye for geometry curvature and can judge the required surface characteristics well, but others simply do not know where to begin. It may be the case that the sizes and shapes that your customer has to deal with day-in day-out are easy to convert, but if there is always going to be a lot of models arriving in STL format and the data has variety of size and diversity of shape, using specialist software designed and dedicated to this task is likely to be more feasible. Some die-hard VX enthusiasts use Geo-magic to convert.

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OldForumPost

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Message 7 of 15

30-01-2007 04:03 . am   |   View his/her posts only
Hi Chris
First let me please draw your attention to the first thread I posted, I'm after examples of parts from point clouds, parts that is with sharp edges. One of my customers asked me for this.

Secondly with regard to the core cavity thing. I realise that the stl file would need to be converted to faces. However I have worked with this part with the help of Enrico, to have a stab at creating the core part without faces. What I did was to move the stl part into a suitable orientation, and then to place curves through points using line of sight to approximate the parting curves. Then creating parting faces is a breeze. All this was done without creating faces as we can easily combine stl and faces in cam and machine it. This is ok for a core type part. The problem occurs when I have to mill a cavity part, this time the stl (or faces) needs to be split.

A couple of things that would help:-

1) The faces analyze command would be useful to get an idea where the split should be, but this does not work on stl files.

2) The ability to split the stl file with a complex shape (curves or faces).

3) I can convert the stl filt to a point block and then erase the points I don't need and then convert back to stl, but this is not as nice as it could be because I can only erase the points based on a sphere, If I could do this using other methods that would be great.

4) Of course if I could easily convert the stl file into faces that would be great.

If you would like me to raise PCR's for any of the above, please let me know.

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ChrisWard2k2

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Message 8 of 15

30-01-2007 06:15 . am   |   View his/her posts only
Hello Mike

I think it is appreciated at VX Corp that our direction should be towards surface meshing of STL/Point Cloud data if we are to invest time in enhancing this part of the application, rather than further STL handling functions that still would not be good enough for most tasks. Enhancements of this type however are not trivial to code.

Concerning point pick to partion areas of points, there is a much better way:

1) Create a Point Block from the STL (Point Cloud Function, icon menu 2nd from left, top icon)

2) Explode the Point Block (PCF, icon menu 2nd from left, 2nd icon)

3) You can now create point blocks by orientating the view appropriately and then picking the points within a fence (right mouse "poly pick")

It is a good idea to colour-code the new blocks as you go.





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Kyonghun

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Message 9 of 15

05-02-2007 09:10 . am   |   View his/her posts only
To Mike:

Is the posted "Lady.zip" data free of any "copyright" issues? In other words, can it be, say, used as tutorial for making NURBS model that I can post on this forum and share with people with similar questions as your original post?

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Message 10 of 15

07-02-2007 09:02 . am   |   View his/her posts only
I am checking the copyright issue and will get back to you asap.

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OldForumPost

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Message 11 of 15

08-02-2007 03:39 . am   |   View his/her posts only
I got this file from Enrico, He says he got it at a trade show from either Microscribe or from Roland, he can't remeber which, its one of their demo parts. If it is a demo part I would have thought it would be ok to use, but I don't know for sure. One thing I do know is if you can create a tutorial on this (or a similar part) that would be very very useful.

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ChrisWard2k2

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Message 12 of 15

08-02-2007 05:44 . am   |   View his/her posts only
Hello Chaps

I have not been able to find this file on the websites of either Microscribe or Roland - perhaps it was a reseller rather than the actual company. We do not know for sure that we can use the file and therefore we should not use it. Better safe than sorry.

Does anyone have a similar file of their own that can be used to the benefit of all VXers?

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OldForumPost

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Message 13 of 15

09-02-2007 03:35 . am   |   View his/her posts only
Hi Chris,

We have done in our office with Scantech laser a plate where is rose. Attached is the picture. There are about 3.3 millions points.
Would this be good?

Size of zipped file is 17 megs.

Regards,

Humble Noble

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ChrisWard2k2

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Message 14 of 15

09-02-2007 04:57 . am   |   View his/her posts only
Hi Noble

That really is a very nice cloud - may be VXers could send a VX file to their sweetheart for St Valentines Day

Typically, this type of "one sided" cloud is easier to deal with in VX. You can define a 2D boundary Sketch and throw a trimmed surface over the points.

What we are hoping to find is a "360 deg" shape, relatively small (the customer produces toy soldiers), that will be manufactured using injection moulding. Casting processes are easier if the mould is made of a flexible compound that can be cut off, but whatever the manufacturing method, these shapes do tend to have a measure of detail and thus present a challenge to surface.

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OldForumPost

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Message 15 of 15

20-02-2007 09:29 . am   |   View his/her posts only
With respect to the kind offer to create a tutorial for the "lady" part and the worries that it might be a problem using this file. I was so looking forward to getting this tutorial that I was encouraged to speak to Enrico once more. I have spoken to Enrico and he tells me that everybody he can think of had the file at the trade show, and not only that but the trade show was over two years ago so he does not think it would be a problem. So surely it would be ok to use this for a non comercial tutorial. I hope so because I would dearly love to have the tutorial, pease.

Here's hoping.
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