kicad-developers team mailing list archive

["Lorenzo" <lomarcan@...>]

--- In kicad-devel@xxxxxxxxxxxxxxx, Vesa Solonen <vsolonen@...> wrote:

> Oh yes it is, but only because it is currently fully sw rendered. As long 
> as every primitive is drawn also without any caching it's going to be 
> slow.

Helpful tip: Porter-Duff composition (AKA alpha transparency) in general cannot be cached :((

> Do you have any clue where the limit is? If you test Kicadocaml you'll get 
> some idea where your HW is. I also did some testing for lines along the 
> example here: http://www.siafoo.net/snippet/97 by using random vertex 
> points in mouse event and was really surprised how many AAlines r200 can 
> do.

R200 is already a pretty recent GPU. A LOT of machines only use Intels (andBTW we have a lot of P3 and Celeron class boxes around... still at <1GHz speed).

> Isn't vertex buffer objects and frame buffer objects supposed to remove 
> command replay? Clutter makes canvas based opengl drawing possible, so 

The 'dirty trick' I talked about is EXACTLY a frame buffer object (implemented before frame buffer objects :P)

> much nicer to work with than raw opengl. Apples developer library seems 
> to be a good place to look for hints.

Indeed all Apple machines have a later than Radeon 9600 class GPU :D

> I'm actively avoiding it :) I think for prototype and hobby use, mixed 
> smd/through hole is the most convenient. Less holes the better, etc...

Even commercially... a THT component costs 3 times an SMD one in assembly: SMD is chip shooted, most THT are inserted at hand, nowadays... almost nobody still has a THT inserting machine!

And BGA need extra inspection (X-rays or that underscope thingy to look at the molten balls). And, of course, with most BGA components you need at least a 4 layer PCB with microvias (and PCB cost levitates :()

> tin reducer dip. I bet it pays to outsource PCB making any day on 
> commercial basis. It seems just too difficult to get eutectic pads these 

I'd say that without PCB making machines (I mean the fully automatic ones) the outsourcing give you 'perfect' results (if it isn't good they have to redo it for free :D) in at most 4 days, and it cost a little more than my hourly pay :P add the cost of the HM drilling bits, and you spend LESS outsourcing even the prototyping!

And, for hobby use, we can get a fully processed 2 side eurocard (160x100, 35um copper, 2 sides, 2 solder masks, component silk) for about 50 EUR.

> :D you use leadless hasl? It flows so badly that it seems to be the 
> invitation for plugged holes. Not to mention http://nepp.nasa.gov/WHISKER/

As I said, plugged holes are my greater problem :D BTW there is a techniquefor thermal vias: you request <= 0.5mm finished hole and it is guaranteed by the process that they will be plugged :D

> > Oh, and RF is SICK :D I prefer stronger stuff in low frequency (the latest PCB I designed had some traces of over 300
> > mil and a 70A relay soldered on it... BTW the 'oblong hole' feature works as advertised, the pcb factory read the
> > files without troubles)
> 
> I guess it's up to definition what is RF. Some say nothing below GHz, 
> but I'd like to say anything that burns your finger with dielectric 
> heating :D I guess you had a bit thicker than 35u copper on it too? SMPS 
> stuff or car audio or classified?

For me RF is >10 MHz, yet I had some problems one times with the coils positioning (mutual flux:() in a 1.6MHz power oscillator for ultrasonics (well,it's a 50W oscillator, flux IS NOT trascurable :D).

The 300mil board is a somewhat simple appliance... it has a 650W heater running at 24V for safety :D It was a funny board to design, in 160x90 it has 230VAC, 24VAC, 30VDC, 5VDC (regulated by a SMPS) AND the millivolt signal from a termocouple :D just imagine the stuff riding the board when the heater switches (hint: is a wound wire heater -> HIGHLY inductive :D)