Free_electrons Altium Library

[JJalling]

Hi Vincent, (and others)

I have been using Vincent's excellent Altium library (http://www.siliconvalleygarage.com/downloads/altium-library.html) for some time, but one thing puzzles me. Maybe it's just me not using it correct, but when I place a 0603 resistor on a PCB, it doesn't align with the grid. When I create my own footprints, I normally place the component reference at pin 1 or at the center of the component.
What is the idea of the reference location in the 0603 resistor footprint? It's not in the center of the component, and it is not in the center of the pad, but somwhere in between. Why is that?

But thanks again for the great library!!

BR Jonas

[DerekG]

When I create my own footprints, I normally place the component reference at pin 1 or at the center of the component.

Do you mean the component origin?

Normally you would set the component origin at the centre of the component as this simplifies SMD robot programming.

[JJalling]

Ohh never mind. Just got home and had another look at the library. The origin is in the center of pin 1. But isn't it better to have it in the centre of the component? Or is it just a matter of what you prefer?

BR Jonas

[AlfBaz]

The origin is in the center of pin 1. But isn't it better to have it in the centre of the component? Or is it just a matter of what you prefer?

Centre of pad is much better because you want to place the components pads on the grid which is where the traces are routed. This gets you better alignment of traces and pads

[free_electron]

this is a long debate.

normally you indeed place parts using the centroid. ( the gravitational center of a part , found by drawing two diagonal lines from the corners of the bounding box and the intersect point is the centroid )

my gripe with that is if you place 0603 and 0805 parts next to each other they line up on their centers.

for the sake of 'stuffability' i set my snap points to pin1  that way all pins1 line up yielding a tighter packing of parts.

i am reworking the libraries as i am learning some really cool tricks in my new job ( i now run altium all day long as opposed to 30% of my time ) and picked up some trickery from the other pcb designers that have used other tools and found workarounds and cross pollination. that stuff is now finding its way in my library.

anyway. one thing to know about my lib : the silkscreen box around a part is drawn in such a way that , if the boxes 'edge overlap' (meaning the right line of part 1 overlaps the left line of part 2 ) you will still have a 12 mil channel between pads.
so you can always run a 6 mil track with 6 mil gap between parts .

this allows you to pack parts very close together.

of course altium will flag a 'part overlap warning'

i found a trick now around that. by creating an additonal part 'boundary' ,on a dedicated mechanical layer,that is 1 mil smaller on all sides than the silkscreen and defining a rule that the boundary checker  should only analyse that layer you can still stuff parts without having placement errors. if you do overlap you will get an error. touching is ok, edge overlap is ok , beyond edge overlap is not ok.

i will try to upload a new version of the library over the weekend.
lots of new stuff has been added.

[Smokey]

...i am reworking the libraries as i am learning some really cool tricks in my new job ( i now run altium all day long as opposed to 30% of my time ) and picked up some trickery from the other pcb designers that have used other tools and found workarounds and cross pollination. that stuff is now finding its way in my library....

New job?

[SeanB]

Chief board designer at Tesla Motors.......... Now does board design full time, and only works on cars and not hard drives.

[snoopy]

this is a long debate.

normally you indeed place parts using the centroid. ( the gravitational center of a part , found by drawing two diagonal lines from the corners of the bounding box and the intersect point is the centroid )

my gripe with that is if you place 0603 and 0805 parts next to each other they line up on their centers.

for the sake of 'stuffability' i set my snap points to pin1  that way all pins1 line up yielding a tighter packing of parts.

i am reworking the libraries as i am learning some really cool tricks in my new job ( i now run altium all day long as opposed to 30% of my time ) and picked up some trickery from the other pcb designers that have used other tools and found workarounds and cross pollination. that stuff is now finding its way in my library.

anyway. one thing to know about my lib : the silkscreen box around a part is drawn in such a way that , if the boxes 'edge overlap' (meaning the right line of part 1 overlaps the left line of part 2 ) you will still have a 12 mil channel between pads.
so you can always run a 6 mil track with 6 mil gap between parts .

this allows you to pack parts very close together.

of course altium will flag a 'part overlap warning'

i found a trick now around that. by creating an additonal part 'boundary' ,on a dedicated mechanical layer,that is 1 mil smaller on all sides than the silkscreen and defining a rule that the boundary checker  should only analyse that layer you can still stuff parts without having placement errors. if you do overlap you will get an error. touching is ok, edge overlap is ok , beyond edge overlap is not ok.

i will try to upload a new version of the library over the weekend.
lots of new stuff has been added.

I am starting to use the center of the component as the origin in my libraries rather than pad 1 etc. If you need to place a component using a pad you can still do it if you have "smart component snap" enabled in the preferences. This allows you maximum flexibility of placement because sometimes center of component is best and sometimes a pad is best.

Also if you have 3D models embedded in your library component then the DRC ignores the silkscreen overlay and uses the 3D model to check for overlapping violations

cheers

[owiecc]

i am reworking the libraries as i am learning some really cool tricks in my new job ( i now run altium all day long as opposed to 30% of my time ) and picked up some trickery from the other pcb designers that have used other tools and found workarounds and cross pollination. that stuff is now finding its way in my library.

Sound like a great material for the Amp Hour. I'd love to hear some great tips.

[Smokey]

http://www.siliconvalleygarage.com/blog/new-job.html
Very Cool.

[maxpayne]

this is a long debate.

normally you indeed place parts using the centroid. ( the gravitational center of a part , found by drawing two diagonal lines from the corners of the bounding box and the intersect point is the centroid )

my gripe with that is if you place 0603 and 0805 parts next to each other they line up on their centers.

for the sake of 'stuffability' i set my snap points to pin1  that way all pins1 line up yielding a tighter packing of parts.

i am reworking the libraries as i am learning some really cool tricks in my new job ( i now run altium all day long as opposed to 30% of my time ) and picked up some trickery from the other pcb designers that have used other tools and found workarounds and cross pollination. that stuff is now finding its way in my library.

anyway. one thing to know about my lib : the silkscreen box around a part is drawn in such a way that , if the boxes 'edge overlap' (meaning the right line of part 1 overlaps the left line of part 2 ) you will still have a 12 mil channel between pads.
so you can always run a 6 mil track with 6 mil gap between parts .

this allows you to pack parts very close together.

of course altium will flag a 'part overlap warning'

i found a trick now around that. by creating an additonal part 'boundary' ,on a dedicated mechanical layer,that is 1 mil smaller on all sides than the silkscreen and defining a rule that the boundary checker  should only analyse that layer you can still stuff parts without having placement errors. if you do overlap you will get an error. touching is ok, edge overlap is ok , beyond edge overlap is not ok.

i will try to upload a new version of the library over the weekend.
lots of new stuff has been added.

free_electron,

Did you upload the latest library on your site ? Just wondering if this is the latest one and I am missing something.

http://www.siliconvalleygarage.com/downloads/altium-library.html

Really appreciate your effort on this.