Clipping plane does not work on LocalView and segfaults on RemoteView

[0xkhch]

Hello!
I am trying to make a clipping plane using the simple cone example. I want to make the slider that changes the resolution move the clipping plane through the cone.

When I am using vtk_widgets.VtkLocalView(renderWindow) the slider does nothing. If I switch views to vtk_widgets.VtkRemoteView(renderWindow) it seg faults.

Here is my code:

from trame.app import get_server
from trame.widgets import vuetify, vtk as vtk_widgets
from trame.ui.vuetify import SinglePageLayout

from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkRenderingCore import (
    vtkRenderer,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
    vtkActor,
    vtkPolyDataMapper,
)

from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkCommonDataModel import vtkPlane
from vtkmodules.vtkFiltersCore import vtkClipPolyData
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleSwitch  # noqa
# -----------------------------------------------------------------------------
# Trame initialization
# -----------------------------------------------------------------------------

server = get_server(client_type="vue2")
state, ctrl = server.state, server.controller

state.trame__title = "VTK Remote View - Local Rendering"


# -----------------------------------------------------------------------------
# VTK pipeline
# -----------------------------------------------------------------------------
DEFAULT_RESOLUTION = 20
renderer = vtkRenderer()
renderWindow = vtkRenderWindow()
renderWindow.AddRenderer(renderer)

renderWindowInteractor = vtkRenderWindowInteractor()
renderWindowInteractor.SetRenderWindow(renderWindow)
renderWindowInteractor.GetInteractorStyle().SetCurrentStyleToTrackballCamera()

cone_source = vtkConeSource()

clip_plane = vtkPlane()
clip_plane.SetOrigin(0, 0, 0)
clip_plane.SetNormal(1, 0, 0)

clipper = vtkClipPolyData()
clipper.SetInputConnection(cone_source.GetOutputPort())
clipper.SetClipFunction(clip_plane)

mapper = vtkPolyDataMapper()
mapper.SetInputConnection(clipper.GetOutputPort())

actor = vtkActor()
actor.SetMapper(mapper)
mapper.SetInputConnection(cone_source.GetOutputPort())
renderer.AddActor(actor)
renderer.ResetCamera()
renderWindow.Render()

# -----------------------------------------------------------------------------
# Callbacks
# -----------------------------------------------------------------------------


@state.change("resolution")
def update_cone(resolution=DEFAULT_RESOLUTION, **kwargs):
    clip_plane.SetOrigin(resolution, 0, 0)
    ctrl.view_update()


def update_reset_resolution():
    state.clip_position = 0

# -----------------------------------------------------------------------------
# GUI
# -----------------------------------------------------------------------------

with SinglePageLayout(server) as layout:
    layout.icon.click = ctrl.view_reset_camera
    layout.title.set_text("Cone Application")

    with layout.toolbar:
        vuetify.VSpacer()
        vuetify.VSlider(
            v_model=("resolution", DEFAULT_RESOLUTION),
            min=3,
            max=60,
            step=1,
            hide_details=True,
            dense=True,
            style="max-width: 300px",
        )
        vuetify.VDivider(vertical=True, classes="mx-2")
        with vuetify.VBtn(icon=True, click=update_reset_resolution):
            vuetify.VIcon("mdi-undo-variant")

    with layout.content:
        with vuetify.VContainer(
            fluid=True,
            classes="pa-0 fill-height",
        ):
            view = vtk_widgets.VtkLocalView(renderWindow, ref="view")
            ctrl.view_update = view.update
            ctrl.view_reset_camera = view.reset_camera

# -----------------------------------------------------------------------------
# Main
# -----------------------------------------------------------------------------

if __name__ == "__main__":
    server.start()

[alesgenova]

I noticed a couple of issues in your code:

• You're setting the input for the mapper to the output of the clipper, but then you're overriding it again using the output of the cone source
• The range of the slider is not appropriate for the size of the cone: try using min=0, max=0.5, step=0.01 (and DEFAULT_RESOLUTION = 0)

Here is a full working example based on the current cone source example. It works for both local and remote view for me:

r"""
Installation requirements:
    pip install trame trame-vuetify trame-vtk vtk
"""

from trame.app import get_server
from trame.decorators import TrameApp, change
from trame.widgets import vuetify, vtk as vtk_widgets
from trame.ui.vuetify import SinglePageLayout

from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkRenderingCore import (
    vtkRenderer,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
    vtkPolyDataMapper,
    vtkActor,
)

from vtkmodules.vtkCommonDataModel import vtkPlane
from vtkmodules.vtkFiltersCore import vtkClipPolyData

# VTK factory initialization
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleSwitch  # noqa
import vtkmodules.vtkRenderingOpenGL2  # noqa

# -----------------------------------------------------------------------------


@TrameApp()
class Cone:
    def __init__(self, server_or_name=None):
        self.server = get_server(server_or_name, client_type="vue2")
        vtk_objects = self._vtk_setup()
        self._vtk_rw = vtk_objects['renderWindow']
        self._vtk_cone = vtk_objects['cone']
        self._clip_plane = vtk_objects['plane']
        self.ui = self._generate_ui()

    @property
    def ctrl(self):
        return self.server.controller

    @property
    def state(self):
        return self.server.state

    @change("origin")
    def on_origin_change(self, origin, **kwargs):
        self._clip_plane.SetOrigin(origin, 0, 0)
        self.ctrl.view_update()

    @property
    def origin(self):
        return self.state.origin

    @origin.setter
    def origin(self, v):
        with self.state:
            self.state.origin = v

    def reset_origin(self):
        self.origin = 0

    def _vtk_setup(self):
        renderer = vtkRenderer()
        renderWindow = vtkRenderWindow()
        renderWindow.AddRenderer(renderer)
        renderWindow.OffScreenRenderingOn()

        renderWindowInteractor = vtkRenderWindowInteractor()
        renderWindowInteractor.SetRenderWindow(renderWindow)
        renderWindowInteractor.GetInteractorStyle().SetCurrentStyleToTrackballCamera()

        cone_source = vtkConeSource()
        cone_source.SetResolution(6)

        clip_plane = vtkPlane()
        clip_plane.SetOrigin(0, 0, 0)
        clip_plane.SetNormal(1, 0, 0)

        clipper = vtkClipPolyData()
        clipper.SetInputConnection(cone_source.GetOutputPort())
        clipper.SetClipFunction(clip_plane)

        mapper = vtkPolyDataMapper()
        actor = vtkActor()
        mapper.SetInputConnection(clipper.GetOutputPort())
        actor.SetMapper(mapper)
        renderer.AddActor(actor)
        renderer.ResetCamera()
        renderWindow.Render()

        vtk_objects = {
            "renderWindow": renderWindow,
            "cone": cone_source,
            "plane": clip_plane,
            "clipper": clipper,
            "mapper": mapper,
            "actor": actor,
        }

        return vtk_objects

    def _generate_ui(self):
        with SinglePageLayout(self.server) as layout:
            layout.title.set_text("Trame demo")
            with layout.toolbar as toolbar:
                toolbar.dense = True
                vuetify.VSpacer()
                vuetify.VSlider(
                    v_model=("origin", 0),
                    min=0,
                    max=0.5,
                    step=0.01,
                    hide_details=True,
                    style="max-width: 300px;",
                )
                with vuetify.VBtn(icon=True, click=self.reset_origin):
                    vuetify.VIcon("mdi-lock-reset")
                with vuetify.VBtn(icon=True, click=self.ctrl.view_reset_camera):
                    vuetify.VIcon("mdi-crop-free")

            with layout.content:
                with vuetify.VContainer(fluid=True, classes="pa-0 fill-height"):
                    view = vtk_widgets.VtkRemoteView(self._vtk_rw)
                    self.ctrl.view_update = view.update
                    self.ctrl.view_reset_camera = view.reset_camera

            return layout


def main(**kwargs):
    cone = Cone()
    cone.server.start(**kwargs)


if __name__ == "__main__":
    main()

[0xkhch]

I noticed a couple of issues in your code:

* You're setting the input for the mapper to the output of the clipper, but then you're overriding it again using the output of the cone source

* The range of the slider is not appropriate for the size of the cone: try using `min=0, max=0.5, step=0.01` (and `DEFAULT_RESOLUTION = 0`)

Here is a full working example based on the current cone source example. It works for both local and remote view for me:

r"""
Installation requirements:
    pip install trame trame-vuetify trame-vtk vtk
"""

from trame.app import get_server
from trame.decorators import TrameApp, change
from trame.widgets import vuetify, vtk as vtk_widgets
from trame.ui.vuetify import SinglePageLayout

from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkRenderingCore import (
    vtkRenderer,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
    vtkPolyDataMapper,
    vtkActor,
)

from vtkmodules.vtkCommonDataModel import vtkPlane
from vtkmodules.vtkFiltersCore import vtkClipPolyData

# VTK factory initialization
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleSwitch  # noqa
import vtkmodules.vtkRenderingOpenGL2  # noqa

# -----------------------------------------------------------------------------


@TrameApp()
class Cone:
    def __init__(self, server_or_name=None):
        self.server = get_server(server_or_name, client_type="vue2")
        vtk_objects = self._vtk_setup()
        self._vtk_rw = vtk_objects['renderWindow']
        self._vtk_cone = vtk_objects['cone']
        self._clip_plane = vtk_objects['plane']
        self.ui = self._generate_ui()

    @property
    def ctrl(self):
        return self.server.controller

    @property
    def state(self):
        return self.server.state

    @change("origin")
    def on_origin_change(self, origin, **kwargs):
        self._clip_plane.SetOrigin(origin, 0, 0)
        self.ctrl.view_update()

    @property
    def origin(self):
        return self.state.origin

    @origin.setter
    def origin(self, v):
        with self.state:
            self.state.origin = v

    def reset_origin(self):
        self.origin = 0

    def _vtk_setup(self):
        renderer = vtkRenderer()
        renderWindow = vtkRenderWindow()
        renderWindow.AddRenderer(renderer)
        renderWindow.OffScreenRenderingOn()

        renderWindowInteractor = vtkRenderWindowInteractor()
        renderWindowInteractor.SetRenderWindow(renderWindow)
        renderWindowInteractor.GetInteractorStyle().SetCurrentStyleToTrackballCamera()

        cone_source = vtkConeSource()
        cone_source.SetResolution(6)

        clip_plane = vtkPlane()
        clip_plane.SetOrigin(0, 0, 0)
        clip_plane.SetNormal(1, 0, 0)

        clipper = vtkClipPolyData()
        clipper.SetInputConnection(cone_source.GetOutputPort())
        clipper.SetClipFunction(clip_plane)

        mapper = vtkPolyDataMapper()
        actor = vtkActor()
        mapper.SetInputConnection(clipper.GetOutputPort())
        actor.SetMapper(mapper)
        renderer.AddActor(actor)
        renderer.ResetCamera()
        renderWindow.Render()

        vtk_objects = {
            "renderWindow": renderWindow,
            "cone": cone_source,
            "plane": clip_plane,
            "clipper": clipper,
            "mapper": mapper,
            "actor": actor,
        }

        return vtk_objects

    def _generate_ui(self):
        with SinglePageLayout(self.server) as layout:
            layout.title.set_text("Trame demo")
            with layout.toolbar as toolbar:
                toolbar.dense = True
                vuetify.VSpacer()
                vuetify.VSlider(
                    v_model=("origin", 0),
                    min=0,
                    max=0.5,
                    step=0.01,
                    hide_details=True,
                    style="max-width: 300px;",
                )
                with vuetify.VBtn(icon=True, click=self.reset_origin):
                    vuetify.VIcon("mdi-lock-reset")
                with vuetify.VBtn(icon=True, click=self.ctrl.view_reset_camera):
                    vuetify.VIcon("mdi-crop-free")

            with layout.content:
                with vuetify.VContainer(fluid=True, classes="pa-0 fill-height"):
                    view = vtk_widgets.VtkRemoteView(self._vtk_rw)
                    self.ctrl.view_update = view.update
                    self.ctrl.view_reset_camera = view.reset_camera

            return layout


def main(**kwargs):
    cone = Cone()
    cone.server.start(**kwargs)


if __name__ == "__main__":
    main()

Hi, yes you are right I tried your code and it does do what I want it to do. There is a few things I don't understand though:

1. If i copy your __vtk__setup(). To fix said issues I had with the clipping, nothing renders onscreen for some reason. Why is that?
2. Why have it as an object? When are @Property called?