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Thomas Rupp
Member
Username: Harper57

Post Number: 61
Registered: 10-2007
Posted on Tuesday, October 23, 2012 - 12:21 pm:   Edit Post Print Post

I am looking at this tutorial and it describes a process of creating the vehicle's body by using profiles and then the Nurbz By Lofting tool. It seems this would require determining exact cross sections of the desire design. I would like to replicate an existing design, for model making purposes.

I am wondering if there is a way to use the process I've seen explained for other software. In this process one roughly draws an initial profile, then extrudes that multiple times, which does not create a new part but extends the existing extrusion each time. This generates a cage which can then be shaped accurately by moving individual points, usually over photos to assure the right shape.

Can something like this be done using Form-Z 6.5.1 on Mac OS 10.5?

Thanks!
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support@formZ.com
Moderator
Username: Tech

Post Number: 18024
Registered: 04-2001


Posted on Tuesday, October 23, 2012 - 04:39 pm:   Edit Post Print Post

Thomas,

formZ 7 has a Reshape tool that can extend a face while leaving the previous one -- but this tool does not exist in formZ 6...

http://www.formz.com/products/formz/formzTrial.html

If you download the current Trial version and use the Reshape tool with the Keep Edges option, does this allow you to do what you want?
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Thomas Rupp
Member
Username: Harper57

Post Number: 62
Registered: 10-2007
Posted on Tuesday, October 23, 2012 - 10:46 pm:   Edit Post Print Post

Form-Z 7 does not work on my OS. However, in Form-Z 6 I was able to keep extruding a B-Spline while keeping the old section intact by selecting by line, while duplicating one copy and setting the extrusion status to keep. Then I could merge the sections using a boolean operation.

Now let me rephrase the question. Is there a methodology that allows one to roughly form the shape and then by moving points reshape the surfaces to create complex forms? When I select by points I see only the first and last points. Shouldn't there be a point for every location where I clicked to create the B-Spline?

This is how many programs create auto bodies, or animals, etc. Of course those programs may not allow exporting to a file type for rapid prototyping, which is what I want to do.

Or are there other methods by which one can create these kind of forms? I would think that having to determine multiple cross sections to create a form would be a tough way to go.
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Bo Atkinson
Senior Member
Username: Boa

Post Number: 631
Registered: 05-2001


Posted on Wednesday, October 24, 2012 - 03:08 am:   Edit Post Print Post

Thomas,

Your described work flow is somewhat-similar to NURBZ Lofting. Version 7 includes more NURBZ variations with the term Loft. Whereas 6 and earlier simply used the term NURBZ. Though 6 did have facetted Loft. And 6 can accept cross sections to form NURBZ. THe move tool can add as many cross sections as one likes, in a straight line.

By the sound of it, NURBZ in 6, should offer what you want and smooth out compound curves.

Modifying one cross section at a time is easiest with low resolution NURBZ. Increasing resolution as the final steps. OR going back and forth for simplified adjusting, before the final smoothing is done.
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support@formZ.com
Moderator
Username: Tech

Post Number: 18032
Registered: 04-2001


Posted on Wednesday, October 24, 2012 - 10:40 am:   Edit Post Print Post

Thomas,

There are numerous ways to create models in form•Z, and traditionally it is used by accurate modelers that demand specific dimensions across an object, so the tools center around the traditional approach of creating specific sources for object creation.

You can also move nurbs controls, reconstruct nurbs surfaces, merge and attach nurbs, and so forth.

This type of modeling means you need an initial nurbs surface to modify. Perhaps you could begin by loosely tracing the main outlines and creating the initial surface, then you can modify the controls to make it more closely match your image.

If you have too many points, you can use the Reconstruct tool to reconstruct to a lower, more manageable number. For example, you could model the dune buggy body as shown in the tutorial with far fewer cross sections, and create the more elaborate shape yourself with the Edit Controls tool. Most modelers find this to require sculpting skills and also find it somewhat inaccurate, and thus the reliance on accurate cross sections.

------

(Now if you are not trying to make a nice Smooth model of a car, then you might consider drawing a simple facetted elevation of the car, extruding it the width of the car, applying a coarse mesh, and then moving these points...)
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Thomas Rupp
Member
Username: Harper57

Post Number: 63
Registered: 10-2007
Posted on Wednesday, October 24, 2012 - 11:57 am:   Edit Post Print Post

I played around a bit with your last suggestion and can see how that works. Can you recommend which tutorials are best to help understand these features? Also, what steps if any must be done to prepare a mesh model for creating an STL file (or other format) for rapid prototyping?
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support@formZ.com
Moderator
Username: Tech

Post Number: 18039
Registered: 04-2001


Posted on Wednesday, October 24, 2012 - 06:04 pm:   Edit Post Print Post

Thomas,

You might look at the Aubry tutorial for this method. In order to export a file for rapid prototyping, it must be solid (watertight) and geometrically sound. If you build your model as solid from the beginning and maintain it's solidity throughout, you should be able to export to .stl properly.

Both of these areas, nurbs/organic modeling and export to .stl, are ones that significant real experience with several projects is usually required for mastery. There are so many things to understand that a few tutorials are only going to get you started. Sufficient drive to experiment and learn can easily overcome this.
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support@formZ.com
Moderator
Username: Tech

Post Number: 18043
Registered: 04-2001


Posted on Thursday, October 25, 2012 - 08:31 am:   Edit Post Print Post

Thomas,

This tutorial elaborates on that technique:

ftp://ftp.formz.com/pub/formz/PDF_files/tutorials/modeling_aubrey.pdf

STL Export needs to be solid, facetted, triangulated data with no self-crossing faces, so be careful when you are moving points not to move one such that it crosses through another face, especially if you wish to make an STL file.
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Thomas Rupp
Member
Username: Harper57

Post Number: 64
Registered: 10-2007
Posted on Thursday, October 25, 2012 - 03:43 pm:   Edit Post Print Post

If I use the same method in the dune buggy tutorial, as a Nurbz object, it will be a solid, is that correct? If so, can I then revise the initial result by moving points or other techniques to refine the shape?
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Thomas Rupp
Member
Username: Harper57

Post Number: 65
Registered: 10-2007
Posted on Thursday, October 25, 2012 - 03:53 pm:   Edit Post Print Post

Okay, I see that I can, great.