[Solved] I don't understand how to use Techdraw

Discussions about the development of the TechDraw workbench
freedman
Posts: 762
Joined: Thu Mar 22, 2018 3:02 am
Location: Washington State, USA

Re: [Solved] I don't understand how to use Techdraw

Postby freedman » Mon Mar 11, 2019 1:29 am

wandererfan
You're way ahead of me!
Certainly not trying to be, just hungry for knowledge. :)
I'll go look around the code and see what I can learn there, then maybe I can ask some specific questions if I don't get it. I need to learn more about the file formats.
Thanks.
Jee-Bee
Posts: 1809
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: [Solved] I don't understand how to use Techdraw

Postby Jee-Bee » Mon Mar 11, 2019 10:42 am

wandererfan wrote:
Mon Mar 11, 2019 12:37 am
Saving either the simple copy or the original source geometry with the frozen drawing object/document/file should be possible.
I make now a short cut to losing dimentions after updateing.
I thjink about the following structure:

Code: Select all

model_in_drawing
  |_ simple_copy_1 (show)
    |_ dimension_1 on simple_copy_1
    |_ dimension_2 on simple_copy_1
    |_ dimension_3 on simple_copy_1
    |_ dimension_4 on simple_copy_1
after changing model

Code: Select all

model_in_drawing
  |_ simple_copy_1 (hidden but in file)
    |_ [s]dimension_1 on simple_copy_1 --> resolved in simple_copy_2[/s]
    |_ dimension_2 on simple_copy_1 --> lost in sinple_copy_2
    |_ [s]dimension_3 on simple_copy_1 --> resolved in simple_copy_2[/s]
    |_ dimension_4 on simple_copy_1 --> lost in sinple_copy_2
  |_ simple_copy_2 (show)
    |_ dimension_1 on simple_copy_2
    |_ dimension_2 on simple_copy_1 --> shown from simple_copy_1 in another color
    |_ dimension_3 on simple_copy_2
    |_ dimension_4 on simple_copy_1 --> shown from simple_copy_1 in another color
After all dimension are resolved/ removed from _simple_copy_# then remove the simple_copy_#

This way it is more easy when losing dimensions. or better you know which ones are lost :lol:
The difficulty is which faces are the same and dimensions should be coupled on faces as prefered method since they are more stable than edges...
wandererfan
Posts: 2666
Joined: Tue Nov 06, 2012 5:42 pm

Re: [Solved] I don't understand how to use Techdraw

Postby wandererfan » Wed Mar 13, 2019 4:31 pm

Jee-Bee wrote:
Mon Mar 11, 2019 10:42 am
The difficulty is which faces are the same and dimensions should be coupled on faces as prefered method since they are more stable than edges...
OCC HLR (the bit that does the projections for us) doesn't return any information about faces. We have to reconstruct them from the pile of edges that OCC gives us.
Jee-Bee
Posts: 1809
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: [Solved] I don't understand how to use Techdraw

Postby Jee-Bee » Thu Mar 14, 2019 9:18 am

ohhh boy :(
freedman
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Joined: Thu Mar 22, 2018 3:02 am
Location: Washington State, USA

Re: [Solved] I don't understand how to use Techdraw

Postby freedman » Thu Mar 14, 2019 8:10 pm

Jee-Bee »
ohhh boy

No kidding!

It sounds like you request a 2D view (with options) and then access a pile of lines, then place control points on their ends. Put them all together on a sheet and you get a drawing. So if someone (later) saves the pile of lines then an image could be saved. Dimensions must have a link to control points or they aren't valid so they don't have a good location on the sheet. This is just a guess from reading all wandererfans other posts.
Here is a link to the OCC hlr
https://dev.opencascade.org/doc/overvie ... _modalg_10
Last edited by freedman on Thu Mar 14, 2019 9:55 pm, edited 2 times in total.
Jee-Bee
Posts: 1809
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: [Solved] I don't understand how to use Techdraw

Postby Jee-Bee » Thu Mar 14, 2019 9:16 pm

No clue what you meant here.

What basically is the situation is i'm used to Ptc Creo. And in creo there is some hierarchy related to objects.
Int parts the following order from stable to least stable:
  1. planes/ axis /CS (basic stuff without ...
  2. surfaces
  3. edges
  4. points of objects there is a better name for that but i'm lost is now it's late ;)
that same for assemblies
  1. Assembly planes/ axis /CS (basic stuff without ...
  2. part planes/ axis /CS (basic stuff without ...
  3. part objects
  4. surfaces
  5. edges
  6. points of objects there is a better name for that but i'm lost is now it's late ;)
Same is related to objects on a drawing a line related to a edge is easy to break since it change often.
a surface is much more difficult to break since it change a few.
planes are almost imposible to break they can move rotate everything but seldom removed and thus seldom lost.

this is more or less the contex of my response.
wandererfan
Posts: 2666
Joined: Tue Nov 06, 2012 5:42 pm

Re: [Solved] I don't understand how to use Techdraw

Postby wandererfan » Fri Mar 15, 2019 1:41 pm

freedman wrote:
Thu Mar 14, 2019 8:10 pm
It sounds like you request a 2D view (with options) and then access a pile of lines, then place control points on their ends. Put them all together on a sheet and you get a drawing.
That's most of it. You also have to split the edges that are touched by other edges to enable face finding. Then you have to find all the closed regions in the edge pile to make faces. :D

A hidden face removal algorithm in OCC would be a nice add.