Extrude Pipe question.

Roy Klein Gebbinck

I just found out that the _Auto option of the _DmExtrude command is governed by a variable: DMEXTRUDEMODE. With that variable set to 2 this solution is possible:

1. Switch to Front (or Back) view. And then tilt the view slightly so that the outer face of the central pipe can easily be selected.
2. _DmExtend the magenta pipes in one go by window-selecting their end faces (use the Tips widget to select faces instead of entities). To avoid selecting faces of the central pipe you can combine two window selections. Accept the default _Auto option of the command, choose _Limit and select the outer face of the central pipe.

Charles Alan Butler

Thanks Roy Ill give that a test drive.

Charles Alan Butler

Setting the DMEXTRUDEMODE to 2 allows you to Extrude with Limit to mate the connection without combining the objects.
This is exactly what I was looking for.
Thanks

Patrik Sparrman

Try also sweep along path if you want to make a soft pipe

Charles Alan Butler

Another question:
You have near verticle pipes that need to extrude or to be cut at a certain level.
How do you create a plane to extrude too or is there a method for that task?
And I assume the SLICE tool is best to trim the pipes?

Hans De Backer

Draw a box that has its bottom face at the desired elevation.
Then
1. make the nearly vertical pipes a bit too long so you can trim them back to the desired level by subtracting the box
or
2. make the pipes a bit too short and then use the extrude tool with 'unify' extrusion mode and select the bottom face of the box as the limit.

The first method is easier and fastest.
FYI: the DELOBJ setting controls whether the subtracted solid is automatically deleted after performing the subtraction.

Charles Alan Butler

Thank you Sir.
I thought that would be the answer but wanted confirmation from the experts.

Charles Alan Butler

I am finding that when your pipe extends through the subtracting object you are left with a cut off object.
That object is associated with the original object like a group & you need to use the SEPARATE command to make them two objects.
The current layer is applied to the subtract from object. You may now erase the cut off object.

Charles Alan Butler

Question on selecting an object: When you have several objects and you want to select only one of them.
You can select the surface of that object but selecting the entire object is difficult if you can not do a crossing window.
It seems that "select entity" mode only applies to the crossing selection & not pick selection.

Hans De Backer

To avoid extra cleanup work afterwards, the pipe indeed should not extend beyond the subtractor, else you end up with a pipe 3dsolid that consists of two disjunct lumps (that's what they are called in ACIS-modeler speak).

Note that in the dwg world, a surface is an entity type used to represent a thin shell that does not have mass or volume, while a face is a part of the boundary of a 3dsolid entity. So from a linguistic point of view it is perfectly fine to refer to the surface of a solid, but when discussing dwg modeling, it is rather confusing, coming close to blasphemy ;-)

Concerning selection:
The Ctrl key toggles between selection of entire entities like 3dsolids or subentities like faces and edges.
The SELECTIONMODES setting controls which type gets priority during selection: edges, faces or entire 3dsolids.
Regardless which type currently has priority, the Ctrl key allows to invert that priority, so at any time you can choose between selecting a face or 3dsolid by using the Ctrl key.

Note that pressing the Tab key repeatedly will iterate both through faces and 3dsolids found under the cursor.

Charles Alan Butler

Hans,
Thanks so much for the education. It is appreciated.

I am finding out that the QUAD needs to be ON for the Ctrl key to shift from surfaces to object. That method is helpful.
I'm thinking that a toolbar button to set SELECTIONMODES may be needed but maybe I'll get used to the QUAD.
After 16 years of avoiding the 3D world, I have a new enthusiasm for CAD.

Charles Alan Butler

I'm thinking the DMEXTRUDEMODE is another switch that needs to be changed depending on the results you want from the command.
Do you open settings every time you need to change the results?

Hans De Backer

When modeling I use very few toolbars, only 2 or 3. One of them is the Selection Modes toolbar, mainly as an indicator of the current flags.
To avoid having to move my cursor to that toolbar to toggle the current mode and then move it back to the work, I assigned two keyboard shortcuts to toggle Face selection and Boundary detection. E.g. to Shift+Ctrl+B I assigned following command expression which toggles Boundary detection: '_setvar;SELECTIONMODES;$M=$(if,$(>,0,$(getvar,SELECTIONMODES)),4,$(xor,$(getvar,SELECTIONMODES),4))

To switch Face selection priority, the command expression is
'_setvar;SELECTIONMODES;$M=$(if,$(>,0,$(getvar,SELECTIONMODES)),2,$(xor,$(getvar,SELECTIONMODES),2))

Coming to think of it, this probably looks daunting, so after a quick check I noticed that the 'Tools' panel of the 'Keyboard' tab on the Customize dialog already contains tools that do exactly that. They can be found in the 'Select' toolbox.

Concerning DmExtrudeMode, we found that there seem to be 2 user types: the 'mechanical' user, who most of the time prefers that when using AUTO mode, the extrusion is unioned with the 'source' object, as opposed to the 'architectural' users, who prefer the AUTO option results in creating new independent extrusion solids.
These different user types will set the DmExtrudeMode flag 1 to a different value.
Please note that this setting only controls the extrude behavior that will be applied when using the AUTO option.
After starting DmExtrude it remains possible at all times to explicitly choose the desired extrusion mode by tapping the Ctrl key: the Tips window displayed at Center-bottom of the screen indicates the active extrude mode.

Charles Alan Butler

Very valuable information.
I love toolbars & hate the ribbon, old school I guess. Command line sometimes.
I use Chief Architect currently for Architectural design & before that Arch-T add-on for Autocad.
Currently, I have some opportunities to do Structural detailing. I love mechanical things, so this 3D has become my new passion.
We'll see how it goes. I'm going to demo Mech-Q and see if the automation is worth the cost.
Current 3D workspace attached.

Charles Alan Butler

Oh and I use the pallet a lot in 2D.

Some of my 3D from Chief Architect https://sketchfab.com/ab2draft/models

Charles Alan Butler

Another question.
I have a small pipe & want to extrude into a larger pipe.
Using the dmextrude MO SO Limit on the face of the end of the smaller pipe and limit to the surface of the larger pipe.
I want the smaller pipe to be one solid and the face molded to the larger pipe surface.
The larger pipe should not be joined to the smaller pipe or changed in any way.
What setting should I use? dmextrudemode doesn't seem to work.

Roy Klein Gebbinck

@Charles Alan Butler:
If by 'into' you mean the extended smaller pipe will interfere with the larger pipe then using the _Auto option will not give the desired result. Try using the _Create option and then _Union the new solid with its 'parent'.
If the extended pipe merely touches the other pipe then choosing the _Auto option with DMEXTRUDEMODE set to 2 should work (as explained above).

I have sent in a support request regarding the DMEXTRUDEMODE setting requesting an additional flag. It may be helpful if you do so as well to provide the Bricsys developers with your particular scenario.

Charles Alan Butler

Thanks for the reply.
I have dmExtrudemode set to 2
Using dmExtrude MO SO & select the yellow pipe end face
Enter Limit & select the outer face of the magenta pipe
The result is the connection I desire. A saddle fit of the yellow pipe to the magenta pipe without joining.
The issue I have is that the yellow pipe is in two parts. The original pipe & the extruded part I created.
When you select one end of the yellow solid they highlite & act as one solid but clearly are not.
Picture attached

Hans De Backer

The yellow pipe really is a single solid ;-)
The unexpected behavior stems from the end face of the yellow pipe being not exactly perpendicular to the axis of the pipe.
So when using that face as the base face for the extrusion towards the magenta pipe, the extrusion direction is slightly different from the axial direction of the yellow pipe, resulting in a slight jog in the yellow pipe, so instead of having a single cylindrical exterior face, the exterior of the pipe now consists of two cylindrical faces at a slight angle...

Roy Klein Gebbinck

@Hans De Backer:
I thought the revised BimConnect command would be able to connect the two pipes. I believe you were referring to this command previously. But this does not work for some reason (V18.1.03). Can you explain why?

Charles Alan Butler

Hans, I see now that the pipe changes directions.
Question now is why did it change directions?

Hans De Backer

@Roy,
in its current implementation, BimConnect can connect pipes or profiles ( = 'linear' solids ) provided their axis lines are coplanar. If they are not coplanar, no intersection between these axes can be found, which will cause the connection to fail
In a future implementation we plan to allow for eccentricity of the axis lines and thus relax the conditions to support connections.

@Charles,
the reason the pipe changes directions is the end face of the pipe not being perpendicular to the axis.
How that came about I can only guess: how has this pipe been modeled?

Charles Alan Butler

Oh, I guess I did that with a slice. As this is a practice drawing I had a saddle face from a previous operation, moved the pipe back away from the larger pipe & attempted to make a fresh face with a perpendicular cut using the slice command.
I must have botched that operation somehow. This 3D is quite a leap for my comfortable 2D world. I seem to be making all kinds of errors and
like this one never knew it happened.

Charles Alan Butler

Just tried slice again. Looks to me as though SLICE does not honor ORTHO mode.
Using a line to snap too I was able to square off the cut.

Charles Alan Butler

OK with dmExtrudemode = 2
I was able to extrude with the desired results when the pipe face was perp to the axis.
Thanks