very good work.
your voice is not very clear in the video.
Can you please list down the benefits of working in blender as I have
almost no experience in blender.
Is it possible to modify the openscad model through blender tools?

On Sun, 24 Apr 2022 at 13:08, emogenet@gmail.com wrote:

On Sun, Apr 24, 2022 at 6:01 PM Sanjeev Prabhakar sprabhakar2006@gmail.com
wrote:

Thank you!

My apologies, last week was my first time recording videos, it'll get
better :)

Blender is a free, very complete 3D environment: modeling, animation,
texturing, shading, rendering, compositing, etc ... it's all there under
one roof.

It was originally designed for special effects work, but it is now very
general and its 3D navigation, mesh manipulation and rendering is top notch.

People use it nowadays for far more then SFX: CAD, Archi, design, painting,
etc ...

Here's a very recent example of a non SFX use:
https://www.youtube.com/watch?v=92QmjS-xDaI

Plus the feature list is essentially bottomless (I think it's 30 years old
software and it has plugins for everything).

I personally find its GUI vastly more powerful than the native OpenSCAD UI
for manipulating 3D meshes.

Yes.

More precisely, Blender has two work modes:
- destructive (direct mesh edition)
- non-destructive (geometry nodes).

In the destructive mode, all changes you make to an OpenSCAD mesh will
disappear if you change the OpenSCAD code and re-generate the mesh.
So, in that mode, you "bake" the OpenSCAD model once and for all and then
edit it further with Blender.

In the non-destructive mode (geometry nodes) you work in a setup similar to
OpenSCAD: every time you change the OpenSCAD code, everything gets
recomputed: the OpenSCAD mesh and all the geometry nodes you applied to it
subsequently.

The one downside to Blender: the initial learning curve is a little steep.

However:
- once you start to master it it's amazing
- there are tons of tutorial videos on YT

My personal take: once I finish this, I will make all my parametric CAD
models exclusively within Blender.

Hope this helps,

- Emmanuel

I watched the video, and I am unclear how this offers any advantage over
developing the geometry in OpenSCAD, generating an STL file, and then
opening the STL file inside Blender.

You say that Blender has better "3D navigating": can you provide an
example?  I've not had any problems with 3D navigation in OpenSCAD itself.

On 4/24/2022 3:38 AM, emogenet@gmail.com wrote:

I believe that the correct answer is "no".  It is possible to modify the
OpenSCAD mesh using Blender tools, but nothing that you do in Blender
can modify the OpenSCAD model (source code).

On 4/24/2022 12:50 PM, Emmanuel Mogenet wrote:

On Sun, Apr 24, 2022 at 8:52 PM jon jon@jonbondy.com wrote:

To answer your question directly, the workflow you describe is slower than
having everything within the same software, especially if you have to
iterate.

Specifically, the workflow you describe makes the "change code" -> "see
object" -> "figure out what to change" -> "change code" -> ... etc very
slow, especially when the "figure out what to change" involves measuring
anything on the resulting geometry.

As discussed in another post on this thread, OpenSCAD sorely lacks
introspection features (you can't compute things like the centroid or the
bounding box of an object programmatically and use the result as a
parameter controlling the behavior of other objects).

For example: placing a sphere at the center of mass of a complex assembly
is very hard to do in OpenSCAD.

Or more simply, placing four spheres at the corners of a cube that has been
rotated and scaled at the bottom of a piece of code that's in a library is
almost impossible to do in OpenSCAD.

There are many more examples, but here is where I find the current SCAD UI
very limiting:
- you can't measure the dimensions of anything
- you can't compute the area / volume of things
- you can't compute the centroid of an object or a set of vertices
- it is very hard to display parts of the objects (cross sections for
example), you are obliged to do it with CSG ops in the scad code itself.
It's a PITN because these "visualization cuts" are typically ephemeral,
only needed to look briefly at hidden things.
- you can't visualize details of the computed geometry with the same
level of details you can in Blender (normals, x-ray mode, shading, matcap
shading, etc...)

Blender comes with all of these features built-in.

Sure, and this what follows is just a bunch of very simple examples

In Blender, when you want to focus the camera on a very specific part of an
object, here's the sequence:
- Press 'Tab' (got to edit mode)
- Press '1' (vertex select mode)
- Drag a small selection square around the set of vertices you want to
focus on
- Press 'NumPad 1' (center viewport camera + zoom on selection)
I don't know how to do that in SCAD.

Here's another: say you want to view a cross-section of a complex object.
In Blender:
- Move the camera to a desired position
- Press 'Alt+B'
- Draw the cross-section box
- All subsequent workflow displays only the part of the object within
the clipping frustum you just defined
Same thing: AFAIK, no equivalent feature in SCAD UI.

Navigate to different "special" views:
- Press 'Numpad 1' : Front view
- Press 'Numpad 7' : Top view
- Press 'Numpad 4,6,8,2' : rotate resp. left, right, up, down by 45
degrees
etc ...
- Press 'Z' then Press '8' : fully lighted / rendered scene with lights
/ shadows / shaders
- Press 'Z' then Press '6' : standard unshaded solid mode (but with
possibility of making parts of the object transparent)
- Press 'Z' then Press '2' : wireframe mode
SCAD does offer some keyboard shortcuts for changing to special views,
but far less than Blender.

Hide / Show parts of the object
- 'Tab' : Edit mode
- '3'  : Facet mode
- Click + Drag: select a bunch of facets
- H : Hide facets

AFAIK, OpenSCAD UI doesn't know about facets of an object, much less how to
hide them

The two UI's simply aren't in the same league when it comes to 3D
navigation.

When I am finished with adding features to this project, I'll try to make a
video to demonstrate some of the above visually by building an object from
scratch with OpenSCAD-in-Blender.

Hope this clarifies,

• Emmanuel

To try and answer your question:

a) the whole point of this project is to be able to modify the OpenSCAD
code directly in Blender, using Blender's built-in text editor and seeing
the result in the quickest possible way (by pressing Alt-U). But I don't
think that's what you meant.

b) No, indeed you are correct, if you apply changes to the mesh produced
by OpenSCAD using Blender native mesh editing tools, these can't be
retrofitted into the OpenSCAD source code. This would be really tricky to
do :)

However: if you apply a bunch of Blender's geometry nodes to your OpenSCAD
mesh, these are essentially a succession of transforms and mesh edits
applied non-destructively (they are remembered), and any change to the
OpenSCAD code will trigger the recompute of the entire chain, so you get
the best of both worlds.

On Sun, Apr 24, 2022 at 8:54 PM jon jon@jonbondy.com wrote: