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I'm new to Alibre, coming from a background in Blender and ZBrush, and a class on Solidworks that ended this winter. I have a lot of questions about how to accomplish certain things in Alibre compared to SW, scenarios I run into where things work differently and I'm not sure of the best way to get the same result. I'm likely to find more but I'll start with these.

Example 1: Midpoints
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In Solidworks (I still have a limited time student activation from the class) I can apply a constraint to the midpoint of a line by hovering over it. For example I could apply a horizontal constraint to the midpoint of the left line and the origin. Or, draw something directly on the midpoint and it would be set as coincident.

Screenshot 2022-01-30 030140.jpgScreenshot 2022-01-30 030928.jpg

In Alibre I can draw some shapes directly on the midpoint but it seems unavailable for constraints. The only workaround I could figure out was to draw a line on the midpoint then set the endpoint of that line to vertical, which also forced the rectangle to center on the midpoint. I'm wondering if there's a better way to do this without the workaround.

Example 2: Face Center and Corner Snapping
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If I want to find the center of a face in Solidworks I can use, in the case of this rectangle, the method where you hover over the midpoints then use the smart-guides to mark the center point. Or in other cases draw supporting reference geometry. In this case I click one corner and then the diagonal opposite, the midpoint of this line is the center. The ends of the line are automatically snapped to the corners of the reference face with a coincident constraint.

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In Alibre if I try this the line firstly doesn't want to snap to anything on draw. If I select the coincident constraint on the endpoint then hover over the edge of the face, it highlights blue but still won't snap to the corner of the face, only the edge.
Screenshot 2022-01-30 042345.jpg
My solution was to project the whole face onto sketch while maintaining association. It just seems like such a roundabout way of anchoring the sketch that I feel I must be doing something wrong though. Is there a better way to do this?

Question 3: Is there a way to project at an angle, for example if you have a sketch plane at 45 degrees 2 cm over a horizontal face, can you project features straight vertical instead of from the 45 degree plane?

Question 4: How, If possible, do you export to a mixed Quad/Tri mesh instead of a fully triangulated .STL. It could be very useful for example on a smooth model, like a water bottle, jet plane, car body. There doesn't appear to be any other format Blender or ZBrush can open, .ZPR was deceptive :p
 

DavidJ

Administrator
Staff member
Question 1: what is it that you actually want to achieve? You can place a Node on the mid point then constrain that. I suspect that for many things that you might be wanting to achieve there are other options.
 
Question 1: what is it that you actually want to achieve? You can place a Node on the mid point then constrain that. I suspect that for many things that you might be wanting to achieve there are other options.
Yes, this is just a simple example but I've been working on a printer enclosure and I wasn't sure if I could select the midpoint directly like I was used to (in solidworks). Some actions, like drawing a line would show the midpoint when I hovered and some would not. The constraints didn't seem to.

Question 2, I noticed with the coincident constraint when I click the endpoint, then the edge, It created a projected reference automatically. Then I could click the endpoint of that line and the one anchored to the arbitrary position along it, and it would narrow the constraint. Proper way to do it? Ie: I want to make sure I'm doing things properly and not picking up bad habits because I missed something. For all I know I just had to hold a modifier key to get the expected behavior or something. :p
 
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DavidJ

Administrator
Staff member
Question 2: No need to project the face (though nothing wrong with doing so).

For example - place a reference line with ends near diagonal corners of face. Select the coincident sketch constraint, fix ends of line to corners (unfortunately you can't do this when initially drawing the line). Then you can place a node at mid point on the reference line.

[EDIT - to do this easily you have to adjust the Selection Filters (in 2D sketch mode, Tools -> Selection Filters -> Solids - make sure an option including Vertices is active. Unfortunately this setting is not remembered form session. Otherwise you can use the intersection constraint to fix line end to where edges meet ]

There are other options - also check settings in 2D sketch mode - snap & constraint settings, to see which inferred constraints are enabled to be offered when sketching.
 
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DavidJ

Administrator
Staff member
Question 3: Sketch projection is always perpendicular to the plane or face that you are sketching on - so position your sketch plane accordingly.
 

DavidJ

Administrator
Staff member
Question 4: Not possible.

[EDIT - but you can adjust export options to give some control of the mesh]
 
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Question 2: No need to project the face (though nothing wrong with doing so).

For example - place a reference line with ends near diagonal corners of face. Select the coincident sketch constraint, fix ends of line to corners (unfortunately you can't do this when initially drawing the line). Then you can place a node at mid point on the reference line.

[EDIT - to do this easily you have to adjust the Selection Filters (in 2D sketch mode, Tools -> Selection Filters -> Solids - make sure an option including Vertices is active. Unfortunately this setting is not remembered form session. Otherwise you can use the intersection constraint to fix line end to where edges meet ]

There are other options - also check settings in 2D sketch mode - snap & constraint settings, to see which inferred constraints are enabled to be offered when sketching.
I'm not sure I follow. If I select a face and open a sketch, I can draw the line, however when I select the coincident constraint, the corner vertex does not appear as a snapping point, only the edge itself. If I click the edge, a copy is automatically added to my sketch and the endpoint of my first line is now coincident to the projected edge. Now that there is a copy of that edge there is an endpoint for me to add another, second, coincident to, but I can't select the corner to begin with.

In other words, in my test scene it only ever creates a projected copy of the edge, and I can't directly select a corner vertex without first having the endpoint of the projected edge to snap it to.

Even If I create a fresh part it always creates a projected copy of an edge when I apply a constraint. Maybe better if I show you. https://drive.google.com/file/d/1EctXn69nJt8KeTyJR4PnhAvDKoKPTskE/view?usp=sharing
 

Ken226

Alibre Super User
After you uncheck "hide menu", the menu and it's tools button will be available here:
 

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I can now select corners directly. It still creates projected/derived reference geometry of anything I add a constraint to, I'm not sure if this is the normal behavior but it seems to work at least.

BTW, Is there a way to change from the default free/trackball rotation to a locked orbital camera like in most VFX 3D apps? I haven't been able to find it.
 

Ken226

Alibre Super User
I can now select corners directly. It still creates projected/derived reference geometry of anything I add a constraint to, I'm not sure if this is the normal behavior but it seems to work at least.

BTW, Is there a way to change from the default free/trackball rotation to a locked orbital camera like in most VFX 3D apps? I haven't been able to find it.
I'm not certain what your asking.

But at a guess, in the "view" tab, there are preset view orientations you can select.

You can also single click any face or corner of the view cube, to bring a about that orientation.

If you single click the front facing face of the view cube, it rotates the view 90°. Or, you can click a corner of the view cube and drag it to the orientation you want.

Also, you can click/hold anywhere on your part model with both mouse buttons at the same time, and drag the view around.
 

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I'm not certain what your asking, but at a guess, in the "view" tab, there are preset view orientations you can select.

You can also single click any face or corner of the view cube, to bring a about that orientation.

If you single click the front facing face of the view cube, it rotates the view 90°
Not quite what I'm looking for. Imagine you have a cube and rotate your view around it , with the default camera rotation it's easy to have your view roll and give you a skewed angle, like this.
Screenshot 2022-01-30 174402.jpg
It's the same default view as ZBrush and has it's uses, but can be disorienting. In ZBrush you click the lock to y button in views and your camera no longer rolls. In Blender/Maya?/Cura/Lychee/ChiTuBox/etc the locked view is the default, no matter how much you rotate the view the ground plane will be a perfect 90 degrees downwards.

Another way to think about it is the camera being a spinning body vs a tidally locked body.
 

Ken226

Alibre Super User
Ok, I think I understand what your asking.

I've never noticed a feature quite like that, but then I havn't looked for one. I don't recall ever seeing it in Inventor or solidworks either. I don't have much experience with solidworks but I used Inventor for 10 years and don't remember a setting like that.

Perhaps someone more knowledgeable can chime in.


There seems to be about everything, except that.
 
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NateLiqGrav

Alibre Super User
See this help page for info on how to rotate the view.

However I believe holding Shift and using the Arrow keys might do what you want. Unfortunately it doesn't rotate an angle that is a divisor of 90, 180, or 360 - so they never get perfectly aligned again - meaning you would have to use the viewcube or buttons to re-align.
 

HaroldL

Alibre Super User
I'm not sure I follow. If I select a face and open a sketch, I can draw the line, however when I select the coincident constraint, the corner vertex does not appear as a snapping point, only the edge itself. If I click the edge, a copy is automatically added to my sketch and the endpoint of my first line is now coincident to the projected edge. Now that there is a copy of that edge there is an endpoint for me to add another, second, coincident to, but I can't select the corner to begin with.

In other words, in my test scene it only ever creates a projected copy of the edge, and I can't directly select a corner vertex without first having the endpoint of the projected edge to snap it to.

Even If I create a fresh part it always creates a projected copy of an edge when I apply a constraint. Maybe better if I show you. https://drive.google.com/file/d/1EctXn69nJt8KeTyJR4PnhAvDKoKPTskE/view?usp=sharing
What you show in your video is how I constrain to an edge or corner of a face. Once you constrain the sketch figure to an edge a reference figure is projected along that edge along with its end points/nodes. A second constraint is then needed to constraint the end of the sketch figure to the end of the projected reference figure.

Anytime you constrain a sketch figure to an edge Alibre will create a projected reference figure into the sketch that is locked to the selected edge.

Unlike SolidWorks that does allow you to reference edges directly while in the sketch mode, in Alibre you need to apply a constraint to accomplish the same task.


It's the same default view as ZBrush and has it's uses, but can be disorienting. In ZBrush you click the lock to y button in views and your camera no longer rolls. In Blender/Maya?/Cura/Lychee/ChiTuBox/etc the locked view is the default, no matter how much you rotate the view the ground plane will be a perfect 90 degrees downwards.

Another way to think about it is the camera being a spinning body vs a tidally locked body.


You could use the view icons at the top of the window. First select a view that you want (front, top, side, etc.) then use the two bent arrow icons to rotate the view around the screen.
1643606991267.png

You might also try the Reset View icon while in sketch mode, that will set the view normal to the screen and you can use the rotate icons to turn the view about the screen center while it remains normal to the screen. Be aware that clicking twice on the Reset View icon will flip the view from the front to the back.

1643607224392.png

Does that get you what you want?
 

@Ken226

Thanks, the cylinder rotation has some similarities but requires a cylinder/axis while not affecting camera pitch. I'm starting to think Alibre only has the one rotation mode.

@NateLiqGrav

Yeah, it still causes the camera to roll as you rotate, but it's a good trick to know.

@HaroldL

Thanks, I found the option I was looking for in the tools menu. It was hiding due to a checkbox in the system options.
The arrows kind of do the opposite of what I wanted to do, they roll the camera on purpose, but it's good to know that they're there for 2D sketching.
 
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