PCell Designer - Recent Threads

Layout Pcell with dynamic parameters to use for Streach Handles

VS202503112718 — Thu, 05 Mar 2026 09:37:55 GMT

Hi Team,

I am developing a Layout Pcell for a logic gate with stretch handles using skill. (Virtuoso Studio IC25.1)

"Input" is one of the parameter in the Pcell. I am trying to create individual stretch control for each of the "Input" connections. I created an rodObjects for each of the Input connections using function rodCreateRect. Now I am trying to assign each of the objects to a parmeter for strech handles using function rodAssignHandleToParameter.

The problem is each of the object I need to control individually and can't assign to the same parameter. Since the value to the "input" is dynamic. Is there any ways to create as many paramters in Pcell dynamically and Assign handles to it?

Thanks in Advance,
Vinod S B

ISPD 2026 paper: Novel concepts to improve custom layout automation capabilities

Goeran — Tue, 06 Jan 2026 03:59:59 GMT

We are delighted to present a custom layout automation related paper at the International Symposium on Physical Design (ISPD) in March 2026 in Bonn, Germany. The paper intents to introduce novel custom automation concepts that are implemented with the PCell Designer tool.

Paper title: Novel concepts to improve custom layout automation capabilities

Paper abstract:
Custom layout remains predominant in the design of today's analog, RF, MEMS, power-MOS, silicon photonics, package, and other non-digital integrated circuits. Automation in this domain is often impeded by inherent complexity, uncertainty, limited compatibility and capability, and established design paradigms. This paper offers a novel perspective and a set of interdependent concepts to address several long-standing custom automation challenges. We establish partitioning, abstraction, reification, uncertainty, and dialectic motion as theoretical foundations to overcome current limitations. Building on this, we derive and detail several generic, automation-enhancing elementary and practical application concepts, including context-consideration, contracts, abilities, mixins, communication, reactivity, and representation. We demonstrate these improved automation capabilities through various application examples and discuss their potential for future custom design automation approaches.

We plan to submit the GPDK-based application example library, the paper link, and the presentation slides to this community page in March 2026 timeframe.

How to split a shape along a defined line?

Kevin Earls — Wed, 15 Oct 2025 17:12:14 GMT

I've found myself wanting to split shapes into multiple shapes many times. What is the best way to split a rectangle into multiple pieces along lines/or edges that bisects the shape?

The geo->tile command doesn't work on a rectangle.
The geo->bisect command only gives you half the shape and you can't specify the split line.
Any use of land or lor merges any abutting shapes I've already split.
I even looked into dropping into skill to try to use leSplitShape, but that doesn't really create multiple shapes.

Ideally, I'd have one command that takes a named shape (which can contain multiple rectangles or polygons) and a named shape consisting of edges that may or may not bisect the shapes, and return all the shapes, where those shapes which are bisected by the edges are split into multiple shapes along the edges.

Think of a big square where I want to make an asymmetrical tic-tac-toe box out of it.

Anyone have a solution that doesn't take half a dozen complex geo commands, a couple of stretch commands, and a bunch of intermediary measurement steps?

RE: How to split a shape along a defined line?

Kevin Earls — Mon, 20 Oct 2025 19:08:43 GMT

Thank you! This is much more elegant than my approach.

RE: How to split a shape along a defined line?

Andrew Beckett — Sat, 18 Oct 2025 10:23:25 GMT

We don't have (as far as I know) anything direct that does this, but it's not too difficult to achieve with the chop command. The chop command requires a shape (not just an edge), but with a little bit of manipulation this can be achieved. The basic approach I used was:

resize (shrink) the source shape by a small amount (e.g. -0.001)
Chop using everyedge of some shapes to identify the places to split, with these edges grown by 0.001
resize (grow) the results by the same small amount (0.001) to remove the gaps caused by the grown edges

Attached is a pcd.txt file doing this with a gpdk045-based example. I created a custom command to make it a bit clearer. Some pictures showing the steps:

The green (Poly) shape is what is going to be split, and I'm going to use the yellow (Nimp) edges to identify the split points. The custom command I've created "split on edge" has these inputs/outputs:

Here's the method itself - hopefully from this (without showing the geo query editor) you can see it's just doing a grow on the "edges" input, and the edges input above is using the everyedge operator on the splitRegions group.. The resize commands below are sizing down the input shape and then sizing up the results afterwards.

This then gives this result:

Hope that helps! We'll also think whether a more direct (this is not too indirect, though) split command could be added. Note using leSplitShape won't be an option because that's not PCell-safe.

Regards,

Andrew

community.cadence.com/.../Split_5F00_layout.pcd.txt

RE: Importing Pcell previously parameterizing in SKILL into PCD tool

Andrew Beckett — Sat, 05 Jul 2025 17:54:58 GMT

The best approach is usually to create a new cell and then instantiate the existing PCell as an instance, and use the edit props command to configure the instance. You could (if needed) create the instance as a para instance and copy the contents out of it if you don't want the additional level of hierarchy, and that way you can delete any objects that you don't want any more (or not copy them in the first place).

As an alternative, there is the experimental Device→Assimilate PCell menu which attempts to bring in the code for the existing PCell and convert into PCell Designer commands (in many cases though you'll just end up with SKILL blocks). This has not been tested on a wide variety of PCells, so your mileage may vary.

Andrew

Importing Pcell previously parameterizing in SKILL into PCD tool

Colin — Mon, 09 Jun 2025 17:18:35 GMT

Currently, I have a parameterized cell that was made completely with SKILL code. I want to import it into the Pcell designer tool to build on the functionality and make it easier to work on in the future. Is there a way to make this transfer cleanly so that I can preserve the previous parameterized functionalities while also gaining the ability to add new parameters through the PCD?

Pcell Designer Geo Query, how to use xCoord of shape A and yCoord of shape B

EMaz — Fri, 01 Nov 2024 16:50:26 GMT

Hello,

In general, I am interested in identifying points or regions by using an x coordinate of a named shape or group and the y coordinate of another shape or group. As a simple example I'd like to draw a 3-pt path from the upper center of named shape A to the left center of named shape B. In order to do this, I am currently measuring the y distance from the top of A to the center of B and then using Geo Query to generate the 3-pt path as show below. Is there a different approach which does not require measuring?

Thank you

MosaicXY PCD command

Akshata M Patil — Wed, 23 Oct 2024 12:14:46 GMT

Hi Andrew,

Can you please let me know, how can we use the Mosaicxy in the code
I am unable to get this, how to use in my code to array. the group of layers or instance.

Thanks,

Akshata M Patil

RE: MosaicXY PCD command

Andrew Beckett — Wed, 23 Oct 2024 13:14:17 GMT

Akshata,

I tried to move this to the PCell Designer forum but there's an issue at the moment which means that doesn't work.

Anyway, a good explanation of the mosaicxy geo query operator is in the documentation at this link.

Regards,

Andrew

RE: How to set-up a schematic.PCell that maestro can select which corners to simulate?

Andrew Beckett — Wed, 07 Aug 2024 11:06:21 GMT

I moved this into the PCell Designer forum (since we have a dedicated forum for it!).

I don't quite understand how changing corners impacts a schematic PCell. Can you provide more detail?

Perhaps it would be simplest for you to show me - since we know each other, could you email me directly? I can have a screen-sharing session this afternoon.

Regards,

Andrew

How to set-up a schematic.PCell that maestro can select which corners to simulate?

CBuerzele — Wed, 07 Aug 2024 06:47:52 GMT

Hi, with PCellDesigner I created a low schematic PCell where I want to use corner parameters for simulation.

Currently the Designer have to change the instantiated PCell manually to use the other corner parameters. And the designers prefer to do it via maestro as they are used by other devices.

Thanks for your help!

Pcell Designer Geo Query land is identifying para shapes

EMaz — Fri, 02 Aug 2024 17:33:30 GMT

Hello,

I am seeing unexpected results with the land Geo Query operator. It is recognizing layers that are defined in the para group as if they are actually present in the pcell.

elements involved = 1 group, 1 layer, 1 para instance

1) Group: gRouteSigNorth contains metals and vias - see pic - it does not contain MET1

2) Layer: MET1 which can be seen in blue in the picture above. MET1 and is part of a group called gTile, (the donut shapes) and the dut in the center (2 small blocks)

3) para instances: I have several groups which are defined in the para group which also contain MET1. In the para group they are defined in quadrant 1 with origin at 0:0

Question: When I select layer MET1, why is the MET from the para shape highlighted? The red outline below shows the MET1 identified from para instances.

The resulting land gives me two shapes... would like to only have the shape on the top.

Thank you!

RE: Pcell Designer Geo Query land is identifying para shapes

EMaz — Mon, 05 Aug 2024 11:44:13 GMT

Thanks Andrew

Much appreciated.

Erika

RE: Pcell Designer Geo Query land is identifying para shapes

Andrew Beckett — Sun, 04 Aug 2024 19:59:37 GMT

This is (for better or worse - I sometimes wish that we'd changed it in the past, but there's too much risk of it breaking PCells that depend upon the behaviour) the default behaviour of the layer Geo Query when used at the leaf level. In the documentation for the operator, it says:

The body of the geo operator, otherwise all shapes in all levels of hierarchy, including para shapes.

If you want to omit the para shapes, you could put the shapes operator inside the layer operator. The will restrict it to just the shapes in the current cellView and omit the para shapes. Note, the shapes operator doesn't include shapes down through the hierarchy, if you wanted the first part of the layer operator's behaviour (i.e. all levels of hierarchy), then you could do:

layer ("MET1" "drawing")
-- hierarchy (0 32)
---- shapes

Hope that's clear (let me know if it's not!). This comes up rather often, so I'll get a note added to the layer operator to include these approaches.

Andrew

RE: PCell Designer: lor Geo Query Command

EMaz — Tue, 09 Jul 2024 21:21:26 GMT

Excellent!

My apologies for not including the pics, (brain gap).

Many thanks for the crazy fast response, work around and background understanding!

-Erika

PCell Designer: lor Geo Query Command

EMaz — Tue, 09 Jul 2024 20:00:31 GMT

Hello,

I am seeing outputs by an "lor" Geo Query command depending on the technology file. the "lo

Common starting point:

I have a 1umx2um rectangle with 2 quarters of an elliptical polygon (half circles) on both the top and bottom. The 3 shapes are all drawn in the same layer.
I add a polygon command to create a new layer. Within the polygon command I use all 3 shapes as the source. The Geo Query expression is 3 nested lines. The inner most line is a "layer" command which identifies the 3 shapes (rect + 2 half circles). The next line is an "lor" command intended to merge the shapes. The outer most line is a "grow" command.
Layer commands behave the same but the outputs of the "lor" command deviate.

Technology file "A"
1. not sure this matters but this technology has a grid of 0.005um
2. the "lor" command merges the 3 shapes
Technology file "B"
1. this technology has a grid of 0.001um
2. the "lor" command does not merge the shapes, instead it create a polygon with a vertical line towards the right side. The subsequent grow of course does not grow uniformly.

Do you know what could be causing this delta?

Regards,

Erika

RE: PCell Designer: lor Geo Query Command

Andrew Beckett — Tue, 09 Jul 2024 21:12:44 GMT

Erika,

I managed to follow what you are describing (some pictures would have helped!). Anyway, this is certainly related to the grid.

Here's what I get with a grid of 0.005:

and with a grid (I just used "change grid" to alter it):

This is a consequence of the fact that the underlying database layer logical operations split the polygons into multiple shapes if there are more than 195 vertices. Unfortunately the grow operator doesn't handle this correctly (potentially we could deal with this internally - I'll speak with the team tomorrow). Anyway, the good news is that there is a way to handle this. Firstly, add a skill command at the beginning of the code with the following:

gqlSetMaxPoints(100000)

(doesn't necessarily have to be as large as one hundred thousand as you won't hit that with polygons this size, but much bigger than 195). With this, you'll get a smooth polygon with a split in it still:

The split is because the grow operator is still splitting with the default number of vertices (I'll raise this too with the team). This can be fixed by changing the geo expression from:

To:

In other words, another lor around the grow.

At some point (possibly in the next major release) we may increase the default number of vertices to minimise these issues - we've been cautious about doing so in a minor release as it may impact existing PCells. The gqlSetMaxPoints() is our supported way of handling this for now. Setting it in a PCell affects geo operators for the remainder of the PCell.

Regards,

Andrew

RE: Locating PCell Designer

dandadom — Fri, 14 Jun 2024 15:33:19 GMT

Thank you Andrew,

I appreciate the help!

Locating PCell Designer

dandadom — Thu, 13 Jun 2024 18:40:11 GMT

Hello,

I'm quite new to Cadence and I recently started a research position in my university related to analog design. Because I am expected to self start it's been a little difficult to navigate Cadence, and to do my work I need to use PCell Designer. Unfortunately I cannot locate it, is it a separate GUI? or is it integrated in another tool? I can see PCell in my Tools dropdown, but as far as I know that brings me to the mostly depreciated graphical PCell window, and a place to write SKILL code.

I would really appreciate some help to get started, Thank you!

Dominik

RE: Locating PCell Designer

Andrew Beckett — Fri, 14 Jun 2024 15:26:27 GMT

Dominik,

You would need to download the PCD25 (latest hotfix) release from http://downloads.cadence.com and there's a video on installing it here: Installing Cadence PCell Designer (you'll also find other videos in the channel on the right hand side with that link which give introductions).

There's a couple of rapid adoption kits too:

Plus the reference manual can be found in the Custom IC Design section of the Product Manuals page.

Andrew

RE: PCell Designer Reference Document

EMaz — Mon, 03 Jun 2024 15:54:10 GMT

Fabulous - thank you!

PCell Designer Reference Document

EMaz — Thu, 29 Feb 2024 14:02:06 GMT

Hello,

Where can I find a user's guide or reference document for PCell Designer? Several of my colleagues and I are beginning to use the tool extensively but do not have any formal documentation.

Thank you!

RE: PCell Designer Reference Document

Andrew Beckett — Mon, 03 Jun 2024 14:01:56 GMT

Yes. It was published a week or so ago. Log onto http://support.cadence.com and then go to Resources→Product Manuals and then in the Custom IC Design click on the Cadence PCell Designer (PCD2.5) link. You'll see the reference manual.

You can directly get to the product manuals page here.

Andrew

RE: PCell Designer Reference Document

EMaz — Mon, 03 Jun 2024 13:04:11 GMT

Hi, any updates on the Reference Guide? If not, are there any reference to learn more about the table feature under the Control flow?

Thanks