### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [November 8, 2025, 5:04pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/1 "2025-11-08T17:04:16Z")
How to programmatically add the vtkSeedWidget or vtkSphereWidget,then execute widgetManager.enablePicking(), and you can drag the widget with the mouse
Thanks.
---
### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [November 8, 2025, 7:55pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/2 "2025-11-08T19:55:12Z")
Isn’t `placeWidget` working ?
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### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [November 8, 2025, 11:15pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/3 "2025-11-08T23:15:06Z")
My requirement is for the program to automatically generate the vtkSeedWidget upon loading, rather than requiring a mouse click to do so
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### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [November 9, 2025, 9:17pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/4 "2025-11-09T21:17:18Z")
I made a PR to demonstrate how to programmatically place a seed widget:
>
>
> \### Context
> VTK.js is lacking an example to programmatically place a widget.
>
> …
> \### Results
> Improve the seed widget API and enhance its example.
>
> \### Changes
> \- \[x\] Documentation and TypeScript definitions were updated to match those changes
>
> \### PR and Code Checklist
> \- \[x\] \[semantic-release\](https://github.com/semantic-release/semantic-release) commit messages
> \- \[x\] Run \`npm run reformat\` to have correctly formatted code
>
> \### Testing
> \- \[\] This change adds or fixes unit tests
> \- \[x\] Tested environment:
> - \*\*vtk.js\*\*: master
> - \*\*OS\*\*: Windows 11
> - \*\*Browser\*\*: Chrome
---
### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [January 2, 2026, 4:33am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/5 "2026-01-02T04:33:24Z")
It seems that I still can’t programmatically place a widget.
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### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [January 4, 2026, 10:37pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/6 "2026-01-04T22:37:45Z")
Indeed the branch was not merged and got outdated. I just rebased it and merged. Can you try again ?
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### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [January 14, 2026, 2:28am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/7 "2026-01-14T02:28:59Z")
I’m just starting to learn about VTK.js. Could you provide me with a demo that loads 10 VTKSeedWidgets at once by clicking a button (instead of loading one at a time by clicking with the mouse)
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### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [January 14, 2026, 9:36am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/8 "2026-01-14T09:36:11Z")
In the example I shared, You need to call 10 times `AddWidget([x, y, z])` in a for loop.
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### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [January 15, 2026, 12:07am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/9 "2026-01-15T00:07:17Z")
for (let k = 0; k \< 5; k++) {
```auto
widget = vtkSeedWidget.newInstance();
widgetHandle = widgetManager.addWidget(widget);
widgetHandle.setCenter([Math.random(), Math.random(), Math.random()]);
```
}
renderWindow.render();
I successfully loaded 5 vtkSeedWidgets using the code above, but when I click on these vtkSeedWidgets with the mouse, an error occurs：”Uncaught TypeError: Cannot read properties of undefined (reading ‘handleEvent’)“
I can’t drag these vtkSeedWidget with mouse either
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### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [January 15, 2026, 10:07am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/10 "2026-01-15T10:07:15Z")
Can you share your code on codesandbox or something similar ?
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### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [January 19, 2026, 12:31am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/11 "2026-01-19T00:31:25Z")
const fullScreenRenderer = vtkFullScreenRenderWindow.newInstance({
background: [0, 0, 0],
});
const renderer = fullScreenRenderer.getRenderer();
const renderWindow = fullScreenRenderer.getRenderWindow();
const cone = vtkConeSource.newInstance();
cone.setResolution(50);
const mapper = vtkMapper.newInstance();
const actor = vtkActor.newInstance();
// Create an instance of vtkPickerManipulator to constrain movement to a target actor
const manipulator = vtkPickerManipulator.newInstance();
// Set the target actor, which is representing a cone
manipulator.getPicker().addPickList(actor);
actor.setMapper(mapper);
mapper.setInputConnection(cone.getOutputPort());
actor.getProperty().setOpacity(0.5);
renderer.addActor(actor);
// ----------------------------------------------------------------------------
// Widget manager
// ----------------------------------------------------------------------------
const widgetManager = vtkWidgetManager.newInstance();
widgetManager.setRenderer(renderer);
let widget = null;
let widgetHandle = null;
renderer.resetCamera();
////////////////////The code below is what I added//////////////
///////////////////begin//////////////
for (let k = 0; k \< 5; k++) {
widget = vtkSeedWidget.newInstance();
widget.setManipulator(manipulator);
widgetHandle = widgetManager.addWidget(widget);
widgetHandle.setCenter([Math.random(), Math.random(), Math.random()]);
}
renderWindow.render();
//////////////////end//////////////////
// -----------------------------------------------------------
// UI control handling
// -----------------------------------------------------------
fullScreenRenderer.addController(controlPanel);
document.querySelector(‘#addWidget’).addEventListener(‘click’, () =\> {
widgetManager.releaseFocus(widget);
widget = vtkSeedWidget.newInstance();
// Important: set the manipulator of the widget to constrain movement to the actor
widget.setManipulator(manipulator);
// Set the color of the seed (random color)
widget
.getWidgetState()
.getMoveHandle()
.setColor3(
Math.round(Math.random() \* 255),
Math.round(Math.random() \* 255),
Math.round(Math.random() \* 255)
);
// Start placement interaction
widget.placeWidget(cone.getOutputData().getBounds());
widgetHandle = widgetManager.addWidget(widget);
widgetManager.grabFocus(widget);
});
I only added a few lines of code in the vtkSeedWidget example.
---
### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [January 20, 2026, 9:50pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/12 "2026-01-20T21:50:51Z")
Did you try with the master of VTK.js ?
Because I realized that no new release of VTK.js were cut since I merged the PR I talked about above.
---
### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [January 21, 2026, 6:22am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/13 "2026-01-21T06:22:01Z")
I’ve tried, but there are still some errors. You can try the code above. I can’t drag those five vtkSeedWidget
---
### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [January 30, 2026, 3:47pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/14 "2026-01-30T15:47:09Z")
It’s because you need to import the “Glyph” profile:
```auto
import "@kitware/vtk.js/Rendering/Profiles/Glyph";
```
[https://codesandbox.io/p/sandbox/programmatic-seed-widgets-tmqyz5](https://codesandbox.io/p/sandbox/programmatic-seed-widgets-tmqyz5)
---
### Author:  [@fdlyj](https://discourse.vtk.org/u/fdlyj)
#### Post date: [February 24, 2026, 1:21am UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/15 "2026-02-24T01:21:07Z")
the latest version [SeedWidget | VTK.js](https://kitware.github.io/vtk-js/examples/SeedWidget.html) Adding a widget after deleting it will result in an error
---
### Author:  [@finetjul](https://discourse.vtk.org/u/finetjul)
#### Post date: [February 25, 2026, 2:12pm UTC](https://discourse.vtk.org/t/how-to-programmatically-add-the-vtkseedwidget-or-vtkspherewidget/16130/16 "2026-02-25T14:12:43Z")
Should be fixed: [docs(seedwidget): fix SeedWidget example by finetjul · Pull Request #3424 · Kitware/vtk-js · GitHub](https://github.com/Kitware/vtk-js/pull/3424)