free cad cooperation


S

Synk

Hello everyone,



I want to develop software to simulate machining of gears.

I want to write this using c++, wx windows and opengl.

I want to cooperate with CAD developers.



I'm MSc Eng in Mechanical Engineering and some background in C++
programming.



I will have big problem with Boolean operation in 3D.



Maybe somebody could help? Maybe there are open source libraries to do it?



The best scenario would be to find somebody who develop open source CAD.

Use some already made functions to manipulate 3D.

If my project works, it could be implemented to this CAD with GPL license.

There will be benefits for everybody. I will do my project.

This CAD developed, by people who will help me, will receive new module.



I hope somebody will answer.
 
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C

Cliff

Hello everyone,



I want to develop software to simulate machining of gears.

How so? WHY? Covering what processes & Physics?

Good gears are usually *generated*.
I want to write this using c++, wx windows and opengl.

Using what as geometric CAD or CAD/CAM entities, exactly?
I want to cooperate with CAD developers.



I'm MSc Eng in Mechanical Engineering and some background in C++
programming.



I will have big problem with Boolean operation in 3D.

No doubt.
Maybe somebody could help? Maybe there are open source libraries to do it?

Do what, exactly?
Make pictures?
The best scenario would be to find somebody who develop open source CAD.

Use some already made functions to manipulate 3D.

If my project works, it could be implemented to this CAD with GPL license.

There will be benefits for everybody. I will do my project.

This CAD developed, by people who will help me, will receive new module.

For 2D AutoCAD?
I hope somebody will answer.

http://en.wikipedia.org/wiki/Category:Free_computer-aided_design_software
http://sourceforge.net/
 
P

Phlip

Synk said:
I want to develop software to simulate machining of gears.

I want to write this using c++, wx windows and opengl.

Why C++? Why not a soft language, such as Lua?
I want to cooperate with CAD developers.

The cheap, efficient, and open-source end of all CAD research is in games.
Games use soft scripting languages to plug objects together, they use
sophisticated physics libraries to provide rigid objects undergoing
geometric translations and rotations, and they all typically integrate to
provide interactive editing and authoring systems.
I will have big problem with Boolean operation in 3D.

One Tom Plunket once learned a development system called "test driven
development" while writing a system to (IIRC) find the minimum set of
triangles to cover a surface.

Google for open source physics libraries, get the ones that come with unit
tests, and you are almost there.
 
S

Synk

Uzytkownik "Cliff said:
How so? WHY? Covering what processes & Physics?

Good gears are usually *generated*.

I want to simulate machining of gears.
I don't know yet if it will be simualtion of special method for example
Gleason.
The more methods will be implemented, the better aplication will be.

Using what as geometric CAD or CAD/CAM entities, exactly?

I don't know yet. I wanted to use OpenGL. That's why I'm looking
for libraries which manipulate in 3D.


No doubt.

That's why I want to implement knowlegde about gears and use
libraries for boolean operations if such exist.
The problem of Boolean operation in 3D is so wide that it could be
the topic of doctor's thesis.
Do what, exactly?
Make pictures?

Too simulate process of machining.

For 2D AutoCAD?

For 3D. There are many CAD's for 3D but they are usually comercial and
expensive.
 
S

Synk

U¿ytkownik "Phlip said:
Why C++? Why not a soft language, such as Lua?

What is Lua? It's first time I hear about it.
I want the application which will work under Windows and Linux.
The cheap, efficient, and open-source end of all CAD research is in games.
Games use soft scripting languages to plug objects together, they use
sophisticated physics libraries to provide rigid objects undergoing
geometric translations and rotations, and they all typically integrate to
provide interactive editing and authoring systems.

Do you know some?
Could you give examples?
How can I find them?

One Tom Plunket once learned a development system called "test driven
development" while writing a system to (IIRC) find the minimum set of
triangles to cover a surface.

Google for open source physics libraries, get the ones that come with unit
tests, and you are almost there.

I will try to find.
Who is Tom Plunket? Do you know him?
 
P

Phlip

Question: You don't want to simulate the gears rotating together, you want
to simulate a machine grinding a gear out of a blank, right?

Finite element analysis (the brute-force way to simulate interacting
molecules) might be a little hard for the physics libraries involved.
What is Lua? It's first time I hear about it.

Lua is a soft but efficient language. Advanced applications - especially
games - typically use a soft language like Lua as their scripting, for all
their highest level activities.
I want the application which will work under Windows and Linux.

Hello, clue, that's up to you, no matter which technology you pick. Just
don't pick anything by Microsoft or any of their cronies, and you will do
fine!
Do you know some?
Could you give examples?
How can I find them?

www.google.com knows all. Please never post without Googling first, and
always refer to what you searched with Google, so we don't think you are
asking us to do all the research!
Who is Tom Plunket? Do you know him?

You can't have him - he's busy on a game right now. I mean if you google for
his experience learning TDD for the 3D graphics in games, that will get you
closer to understanding how TDD can help finite element simulation.
 
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C

Cliff

Why C++? Why not a soft language, such as Lua?


The cheap, efficient, and open-source end of all CAD research is in games.
Games use soft scripting languages to plug objects together,

But need little precision or accuracy in so doing.
they use
sophisticated physics libraries to provide rigid objects undergoing
geometric translations and rotations,

That's not sophisticated or even Physics.
That's just a simple matrix operation (translation) with probably a
4X4 matrix (very simple linear algebra).
and they all typically integrate to
provide interactive editing and authoring systems.

They might even use large polygons to approximate
analytic or NURBS surfaces ...

BTW, I gather that graphics cards for games don't
well support CAD or CAD/CAM applications so so
code for gamers may not either.
 
P

Phlip

Cliff said:
But need little precision or accuracy in so doing.

You address game physics, not their scripting layers.

Probably true. I would suppose that a physics engine could have a knob for
its precision. You can set it to realtime and get very coarse, and set it to
super-slow and get very high precision. Maybe not.

I suggested game engines because there are indeed programming shops out
there taking the tools invented for gaming and re-purposing them for
industrial situations, such as visualizing machined parts.

You might be correct that games would use a visualization system with much
higher quality than their physics system!
 
C

Cliff

I want to simulate machining of gears.
I don't know yet if it will be simualtion of special method for example
Gleason.
The more methods will be implemented, the better aplication will be.

"Generated".
I don't know yet.

You REALLY need to start with that consideration.
What is possible?
I wanted to use OpenGL.

"OpenGL's basic operation is to accept primitives such as points, lines and
polygons, and convert them into pixels."

You probably need geometric surfaces, not pixels or polygon
approximations.
That's why I'm looking
for libraries which manipulate in 3D.

??
That's why I want to implement knowlegde about gears and use
libraries for boolean operations if such exist.

To do what, exactly?
The problem of Boolean operation in 3D is so wide that it could be
the topic of doctor's thesis.

<Snort>.
The solids modeling kernels .. ParaSolid, ACIS, etc.

BREP geometry vs CSG too ...
Too simulate process of machining.

To "simulate" WHAT "process of machining"?

Planning on a ball endmill with a 5+ axes milling machine?


http://www.google.com/search?num=50&hl=en&ie=ISO-8859-1&safe=off&q="gear+generation"+&btnG=Search

http://www.mech.uwa.edu.au/DANotes/gears/generation/generation.html
For 3D. There are many CAD's for 3D but they are usually comercial and
expensive.

So just for free 3D CAD?
 
C

Cliff

You address game physics, not their scripting layers.

??
Probably true. I would suppose that a physics engine could have a knob for
its precision. You can set it to realtime and get very coarse, and set it to
super-slow and get very high precision. Maybe not.

The part is that bit of stock where the tool's envelope did not go.
Parts are stock that holds the holes (& other features) apart.

CAD & CAD/CAM surfaces & solids (solids are bounded by "faces"
which are usually [perhaps trimmed] surfaces) in BREP models
(contrasted with the now little-used CSG models).
I suggested game engines because there are indeed programming shops out
there taking the tools invented for gaming and re-purposing them for
industrial situations, such as visualizing machined parts.

So all you want are a few pretty pixels?
You might be correct that games would use a visualization system with much
higher quality than their physics system!

CAD & CAD/CAM systems are usually exact to the computational resolution
of the hardware (& software). Surfaces & solids can be interpolated to almost
such precision.
Graphics stuff only need to be within only 1 or 3 pixels, at best, and
is often generated (on the fly as it were) from the underlying CAD or
CAD/CAM geometric model.

How precise do you want to be? Why?
 
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L

lilburne

Phlip said:
You address game physics, not their scripting layers.

Probably true. I would suppose that a physics engine could have a knob for
its precision. You can set it to realtime and get very coarse, and set it to
super-slow and get very high precision. Maybe not.

I suggested game engines because there are indeed programming shops out
there taking the tools invented for gaming and re-purposing them for
industrial situations, such as visualizing machined parts.

You might be correct that games would use a visualization system with much
higher quality than their physics system!

Calculating cutting tool trajectories is normally carried out at the
micron level or less. For simulation and graphic representation a 100
microns of accuracy will suffice.

Meshes might be used in both CAD/CAM and games, but in CAD/CAM such
meshes are generated on the fly from the underlaying mathematical
surface geometry. Such systems may generate two meshes, a coarse one for
visualization, and a finer one for calculating the cutting tool
trajectories.

Of course one could also use the fine mesh for both visualization and
analysis.

However, boolean operations of surfaces is rarely done purely on meshes
nowadays.
 
C

Cliff

You might be correct that games would use a visualization system with much
higher quality than their physics system!

I misread that the first time, sorry.
It's exactly the converse of what you stated.
A one pixel size in a game might be a cubic meter or larger in 3D.
With a CAD or CAD/CAM model surfaces are always the same .... precise
to the undelying mathematics to the compute ability, usually.
The images produced from them for display are in pixels (we used
to have vector displays too ...)

See IGES entity 128 <G>.
 
P

Phlip

Cliff said:
I misread that the first time, sorry.
It's exactly the converse of what you stated.

"CAD requires much higher resolution" is exactly the converse of what I
said?

Ooookay....
 
P

Phlip

Cliff said:
"games would use a visualization system with much higher quality"

A game project:

- coarse physics, just enough so arrows fly on parabolas
and characters don't drop thru pinholes

- advanced graphics, so everything is shiny and dazzly

A CAD project:

- advanced physics, to design reliable hardware

- coarse graphics; enough to visualize things
 
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C

Cliff

A game project:

- coarse physics, just enough so arrows fly on parabolas
and characters don't drop thru pinholes
- advanced graphics, so everything is shiny and dazzly

http://solidworkspilot.com/
A CAD project:

- advanced physics, to design reliable hardware

- coarse graphics; enough to visualize things

http://solidworkspilot.com/

Last I knew pixels were pixels and a monitor had M X N of them.

BTW, You seem to be using the noise "physics" in two different
contexts with two different meanings. Perhaps neither being
accurate to the noise.

Perhaps you were thinking computational tradeoffs for fast animation?


http://www.rockwellcollins.com/about/additionalproducts/RCS/training/visual-products/index.html
http://www.405themovie.com/Home.asp <g>.
http://zoomquilt.org/
 
S

Synk

U¿ytkownik "Dennis (Icarus)" napisa³
and has been, so look at
www.parasolid.com

Ok my question? Is it open source? I don't think because it's from UGS.
I wan't be independent form commercial CAD's because they want to much money
for their applications.
That's why the task is so complicated.
 
D

Dennis \(Icarus\)

Synk said:
That's why I want to implement knowlegde about gears and use
libraries for boolean operations if such exist.
The problem of Boolean operation in 3D is so wide that it could be
the topic of doctor's thesis.

and has been, so look at
www.parasolid.com

<snip>

Dennis
 
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S

Synk

U¿ytkownik "Phlip said:
www.google.com knows all. Please never post without Googling first, and
always refer to what you searched with Google, so we don't think you are
asking us to do all the research!

I have made homework.
I found to libraries that have boolean operations.
http://www.opencascade.org/
http://www.cgal.org/

There are also many publications about computer 3D graphics at:

http://www.siggraph.org/

So now reading, reading and one more time reading ;)

Does anybody, form you, used opencascade or cgal??
 

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