Autoplace stops short and no manual placement?

[anthonyt 0]

I am trying to fill up the platform (using the right-click multiply-object feature in Cura 14.09) with parts that would seem to normally allow 12 pieces on the platform, but only 11 are allowed (warning reported: "Could not create more than 10 items"). See screenshot below.

Then while trying to manually move the parts around, many of the other parts jump to very odd locations including overlapping eachother.

 

Any ideas/solutions on how to fill the build platform completely are very welcome.

 

[pm_dude 27]

Are you printing using print one at a time or print all at once? For the last piece just import another one instead of using multiply.

If you print one at a time:

When moving pieces around you should see a gray shadow on the grid around the selected object representing the free space needed around for the print head to move and not get in contact with other pieces. Move the pieces slowly and you should be able to position the 12 pieces.

You can also try to rotate the piece 90 (around x) to see if you can reduce the required free space around the objects.

 

[anthonyt 0]

Are you printing using print one at a time or print all at once? For the last piece just import another one instead of using multiply.

If you print one at a time:

When moving pieces around you should see a gray shadow on the grid around the selected object representing the free space needed around for the print head to move and not get in contact with other pieces. Move the pieces slowly and you should be able to position the 12 pieces.

You can also try to rotate the piece 90 (around x) to see if you can reduce the required free space around the objects.

 

Thank you for your comments.

I am "printing one at a time".

I tried "importing one more item" and autoplace moved every other piece to weird locations including off the build plate instead of putting that piece where it would fit in the corner, see image below:

The gray shadow seems much smaller than the apparent Cura rule for manual placement. Please try it for yourself. Everytime I move a part so the gray area is still 1cm away from the first part (and its skirt), the first part part jumps 1cm further away. In fact, try this:

 

1. Place one part on the build plate.

2. Multiply that one part 1 copy (a second part will be placed).

3. Then grab that second part and move it 0.5cm away from the first part and notice that the first part moves even further from the second part as shown in the image below. Therefore, manual placement does not observe the same rules as autoplace.

Rotating parts does not help in my case.

I agree that I am trying to cram a lot onto the plate, but there have been times when autoplace put a part in that bottom corner and left another location free, so I know it can be placed there. This makes me think there are differences with the autoplace and manual-place spacing rules.

I think I know the problem now; Manual-place erroneously uses the gray area as the boundary for "all" parts even though it should only use the gray area of one part to the surrounding actual part shapes, and Autoplace only uses the gray area of one part at a time to the actual neighbouring parts (as it should) except for some locations like in my example of that corner part.

 

[pm_dude 27]

The adjacent pieces should be pushed by the same amount it interpenetrate with the gray area. At least that is what happen in 14.07.

After looking at 14.09 it does the same.

Important when moving stuff around. The dark gray areas should not overlap light gray areas. Otherwise they will get pushed away.

 

[Titus 170]

if you print all at once the objects can be put closer together, since there is no risk the head will hit previously printed items. I am struggling with this too.

 

[pm_dude 27]

I was thinking of finding a way to lock the transformation (position, rotation, scale) of objects on the plate so that when you use the reload or reload all objects they stay where they are. That would be useful when iterating on custom supports and stuff like that where the object need to be re-positioned every time it is reloaded.

That could also be a good use case too but it would require a visual representation that the objects overlap in a way that will cause printing issues.

 

[anthonyt 0]

The adjacent pieces should be pushed by the same amount it interpenetrate with the gray area. At least that is what happen in 14.07.

After looking at 14.09 it does the same.

Important when moving stuff around. The dark gray areas should not overlap light gray areas. Otherwise they will get pushed away.

 

Autoplace properly allows interpenetration of one gray area into another gray area as long as one gray are does not penetrate another part shape.

Why are autoplaced parts moved FARTHER away from eachother when a slight manual movement of one part AWAY causes the other part to mover FURTHER AWAY?

Are you saying this is normal behaviour? This seems like a bug to me.

 

[pm_dude 27]

Hey I just flashed on something.

Try reducing the start distance of the skirt to minimal. If you put it to 0.05 it will do like brim so anything between the current start distance and 0.05mm will reduce the light gray area.

 

[anthonyt 0]

if you print all at once the objects can be put closer together, since there is no risk the head will hit previously printed items. I am struggling with this too.

 

Sure "all at once" will solve this problem, but if printing fails part way through, then all parts are garbage.

 

[anthonyt 0]

Hey I just flashed on something.

Try reducing the start distance of the skirt to minimal. If you put it to 0.05 it will do like brim so anything between the current start distance and 0.05mm will reduce the light gray area.

 

That's not the problem. I tried it anyway and it did not help.

The problem is that manual placement considers the gray area of surrounding objects instead of only considering the actual part shape. I think there are two bugs/feature-requests:

 

1. Manual-placement should only use adjacent part shapes, not adjacent part-gray-area (or whatever it is called).

2. Auto-placement should allow all empty space to be utilized on the platform. See my example above that should fit 12 parts but instead leaves a hole.

 

[pm_dude 27]

 

There are 3 shades of gray (red arrows):

- Light gray is the space needed by the entire print head to cover the print area.

- Mid gray is the space the object uses including brim or skirt

- Dark gray is the space the object uses + a small buffer I guess.

 

The auto placement leave a gab (orange circle) between every light gray and dark. It looks to me that the auto placement places the objects using the light and mid gray while in reality the mid gray represent only a single layer on the bed and have no involvement in the print head movements.

The Green circle represent what you can achieve when manually moving pieces around. When I manually move the pieces around, only the pieces having overlap between light and dark gray get moved. The others don't move unless the subsequent pieces being pushed create an overlap to other pieces.

 

[pm_dude 27]

That's not the problem. I tried it anyway and it did not help.

The problem is that manual placement considers the gray area of surrounding objects instead of only considering the actual part shape. I think there are two bugs/feature-requests:

 

1. Manual-placement should only use adjacent part shapes, not adjacent part-gray-area (or whatever it is called).

2. Auto-placement should allow all empty space to be utilized on the platform. See my example above that should fit 12 parts but instead leaves a hole.

 

 

For me the behavior works great as described above. I'm running on Windows 7.

 

[pm_dude 27]

Also consider that the there is probably more than one potential way (in general) to order objects on the bed in order to fit. Depending how many iterations the code does it might not find the best way all the time.

We can see logic that the software doesn't unless it try it very often. Just like the fact that it wont turn the object to minimize total head movement width.

 

[anthonyt 0]

For me the behavior works great as described above. I'm running on Windows 7.

 

That sounds great! (I'm running on Linux).

Would you mind trying my model and auto-place 12 of them on your build platform?

Here is the link to my STL file:

http://unihedron.com/projects/modelview/models/top4x1.stl

 

[anthonyt 0]

There are 3 shades of gray (red arrows):

- Light gray is the space needed by the entire print head to cover the print area.

- Mid gray is the space the object uses including brim or skirt

- Dark gray is the space the object uses + a small buffer I guess.

 

The auto placement leave a gab (orange circle) between every light gray and dark. It looks to me that the auto placement places the objects using the light and mid gray while in reality the mid gray represent only a single layer on the bed and have no involvement in the print head movements.

The Green circle represent what you can achieve when manually moving pieces around. When I manually move the pieces around, only the pieces having overlap between light and dark gray get moved. The others don't move unless the subsequent pieces being pushed create an overlap to other pieces.

 

Thank you for the explanation.

Your orange circle is on the Y axis, and the green circle on the X axis.

The fault exists in my tests where Y-axis manual movements cause extra wasted space to be added. Only X-axis manual movements obey the proper outline overlap rule.

Do you agree with me that there is a bug with manual-placement in that it does not use the auto-placement rule set on the Y-axis?

 

[pm_dude 27]

It worked like a charm instantly with the config of a UM2.

BUT there is a huge extra triangle in the gray area when doing it with a UMO config.

There is definitively a bug when doing it with the UMO

 

[anthonyt 0]

There is definitively a bug when doing it with the UMO

 

Thank you for the confirmation.

Bug submitted here:

https://github.com/daid/Cura/issues/978

 

[Daid 306]

I recently encountered this bug in the PinkUnicorn development version and fixed it there. It has to do with the collision detection code. It sometimes detects collisions that are not there, or fails to detect a collision.

Note that the autoplacement is still funky. It simply works by adding more objects till one object falls out of the printer boundary, and then it removes that one and arranges all objects again. As this also uses the collision function, it might just be bugging out for the same reason as the manual placement.

If you want to test if my changes fix this problem, you can overwrite the "Cura/util/polygon.py" file with the latest version from:

https://github.com/daid/Cura/blob/SteamEngine/Cura/util/polygon.py

 

[anthonyt 0]

I recently encountered this bug in the PinkUnicorn development version and fixed it there. It has to do with the collision detection code. It sometimes detects collisions that are not there, or fails to detect a collision.

Note that the autoplacement is still funky. It simply works by adding more objects till one object falls out of the printer boundary, and then it removes that one and arranges all objects again. As this also uses the collision function, it might just be bugging out for the same reason as the manual placement.

If you want to test if my changes fix this problem, you can overwrite the "Cura/util/polygon.py" file with the latest version from:

https://github.com/daid/Cura/blob/SteamEngine/Cura/util/polygon.py

 

Unfortunately, that did not solve my problem of fitting 12 parts on the platform.

And, it seems to have exaggerated the problem of manual placements; when only two parts are on there (like in my picture above, Y axis movements on one part causes the other close part to move very oddly. Moving one part away slightly (in the Y direction) causes both to move to the front of the build plate or the other part to move closer to the moving part.

 

[pm_dude 27]

Daid, why is there a difference in the collision detection when using the UMO config vs the UM2?

[peggyb 170]

I tried your file and copied to 12 on a UMO, Cura 14.06-RC6. It works….

At first in the layer view they loaded everything like 'print all at once' although 'print one at a time' was selected; strange.

Then I did a 'reload all objects' and everything looks good.

 

[pm_dude 27]

Good. At least it can work in 14.06.

 

In 14.07 it looks like this. UM2 config on top UMO below.

Is this really the shape that should be have the light gray area for the UMO?

 

[anthonyt 0]

tHANKS

 

I tried your file and copied to 12 on a UMO, Cura 14.06-RC6. It works….

At first in the layer view they loaded everything like 'print all at once' although 'print one at a time' was selected; strange.

Then I did a 'reload all objects' and everything looks good.

 

Thank you very much for that workaround, it worked perfectly on Cura 14.09:

 

1. Tools -> "Print all at once".
   
2. Load one model.
   
3. Right click on model and "multiply object".
   
4. Tools -> "Print one at a time".
   
5. File -> "Reload Platform".
   

Now I can print a full platform of objects one at a time.