Hello everyone, I’m new here and just starting out with pyRevit.
For practice, I’d like to recreate the “Member” button under Analyze to place an analytical member between two points. I imagine I need to use the PickPoint class to select the two points and then pass them to the class that represents analytical members (which I haven’t been able to find).
Do you think this is too complicated as a starter example?
My attempt is
with Transaction(doc,'test') as t:
t.Start()
p1= uidoc.Selection.PickPoint()
p2= uidoc.Selection.PickPoint()
line = Line.CreateBound(p1,p2)
analine = AnalyticalMember.Create(doc,line)
t.Commit()
it seems working fine but I am just picking two points and then the element is visualised. I wonder if there is a way to create a preview of the line
Hi, welcome
What are the exact steps you would like to go through or have?
4b. Cancel and exist the script
?
Jean-Marc, thank you
In the code above, the user selects two points, and an analytical member is then drawn. What I would like to implement is a kind of preview, similar to what we see when drawing a line in Revit. After selecting the first point, a line should be visualized dynamically according to the position of the pointer.
I am wondering whether, instead of requiring two picked points, I could use a Line class and then convert it into an analytical member. I would like to know if I am on the right track or if I am overcomplicating the approach.
Thank you.
I don’t think what you’re looking for can be done directly via revit API.
You could draw a preview of what you’re creating via the direct context 3d interface, but that however is an overcomplicated approach to this imo.
Anyway, I tried to implement sth like you’re descriping with the help of AI, quite fun, but not sth worth rolling out into a productive environment.
Here’s the code in case anyone has a similiar usecase, the custom tooltip by thebuildingcoder can be used a baseline to start with as well.
from pyrevit import framework, revit, HOST_APP, script, forms
from pyrevit import DB, UI
__persistentengine__ = True
# Global state
dc3d_server = None
tracker = None
idling_handler = None
selection_handler = None
p1 = None
p2 = None
ui_instance = None
def create_line_mesh(start, end, color=DB.ColorWithTransparency(255, 0, 0, 0)):
edge = revit.dc3dserver.Edge(start, end, color)
mesh = revit.dc3dserver.Mesh([edge], [])
return mesh
def create_cube_mesh(center, size=0.3, color=DB.ColorWithTransparency(255, 0, 0, 0)):
bb = DB.BoundingBoxXYZ()
bb.Min = DB.XYZ(-size, -size, -size)
bb.Max = DB.XYZ(size, size, size)
bb.Transform = DB.Transform.CreateTranslation(center)
mesh = revit.dc3dserver.Mesh.from_boundingbox(bb, color, black_edges=True)
return mesh
def get_mouse_model_point():
ui_view = revit.active_ui_view
if not ui_view:
return None
# --- 1. Get the current Windows mouse position ---
p = framework.Forms.Cursor.Position
# --- 2. Get the Revit UIView window rectangle ---
rect = ui_view.GetWindowRectangle()
# Check bounds
if p.X < rect.Left or p.X > rect.Right:
return None
if p.Y < rect.Top or p.Y > rect.Bottom:
return None
# --- 3. Compute relative mouse position inside the view ---
dx = float(p.X - rect.Left) / float(rect.Right - rect.Left)
dy = float(p.Y - rect.Bottom) / float(rect.Top - rect.Bottom)
# NOTE: dy uses Bottom->Top order because Windows Y grows downwards
# --- 4. Convert to model coordinates using zoom corners ---
corners = ui_view.GetZoomCorners()
a = corners[0] # bottom-left point in model coords
b = corners[1] # top-right point in model coords
v = b - a # diagonal of the view box
# Build the point in model coordinates
q = DB.XYZ(
a.X + dx * v.X,
a.Y + dy * v.Y,
a.Z + dx * v.Z # Perspective views have z variation
)
return q
class MouseTracker:
def __init__(self, start_point, dc3d_server_instance):
self.start_point = start_point
self.dc3d_server = dc3d_server_instance
self.is_active = False
self.last_mouse_point = None
self.frame_skip = 0
def on_idling(self, sender, args):
"""Called during Revit's idle time"""
if not self.is_active:
return
self.frame_skip += 1
if self.frame_skip < 2:
return
self.frame_skip = 0
try:
mouse_point = get_mouse_model_point()
if mouse_point is None:
return
if self.last_mouse_point is not None:
delta = mouse_point.DistanceTo(self.last_mouse_point)
if delta < 0.1:
return
self.last_mouse_point = mouse_point
line_color = DB.ColorWithTransparency(0, 255, 0, 100)
preview_line = create_line_mesh(self.start_point, mouse_point, line_color)
# Show start point cube and preview line
start_cube = create_cube_mesh(
self.start_point, 0.2, DB.ColorWithTransparency(255, 0, 0, 0)
)
self.dc3d_server.meshes = [start_cube, preview_line]
revit.uidoc.RefreshActiveView()
except Exception as e:
print("Error in mouse tracking: " + str(e))
def start(self):
self.is_active = True
def stop(self):
self.is_active = False
def on_selection_changed(sender, args):
"""Triggered when user clicks in Revit view after selecting p1."""
global tracker, selection_handler
# Trigger second pick
ui_instance.end_event.Raise()
# External Event Handlers
class PickStartPointHandler(UI.IExternalEventHandler):
def Execute(self, uiapp):
global p1, tracker, idling_handler, dc3d_server, ui_instance, selection_handler
try:
p1 = revit.pick_point("Pick start point")
if p1:
# Show start point cube
start_cube = create_cube_mesh(
p1, 0.2, DB.ColorWithTransparency(255, 0, 0, 0)
)
dc3d_server.meshes = [start_cube]
revit.uidoc.RefreshActiveView()
# Set up mouse tracking
tracker = MouseTracker(p1, dc3d_server)
idling_handler = framework.EventHandler[UI.Events.IdlingEventArgs](
tracker.on_idling
)
HOST_APP.uiapp.Idling += idling_handler
tracker.start()
selection_handler = framework.EventHandler[UI.Events.SelectionChangedEventArgs](on_selection_changed)
HOST_APP.uiapp.SelectionChanged += selection_handler
# Update UI state
if ui_instance:
ui_instance.Dispatcher.Invoke(
framework.System.Action(ui_instance.update_after_start_point)
)
except Exception as ex:
print("Error picking start point: " + str(ex))
def GetName(self):
return "Pick Start Point Handler"
class PickEndPointHandler(UI.IExternalEventHandler):
def Execute(self, uiapp):
global p1, p2, tracker, dc3d_server, ui_instance, selection_handler
try:
if selection_handler:
try:
HOST_APP.uiapp.SelectionChanged -= selection_handler
except:
pass
selection_handler = None
p2 = revit.pick_point("Pick end point")
if p2:
# Stop tracking
if tracker:
tracker.stop()
# Show both points and final line
start_cube = create_cube_mesh(
p1, 0.2, DB.ColorWithTransparency(255, 0, 0, 0)
)
end_cube = create_cube_mesh(
p2, 0.2, DB.ColorWithTransparency(0, 0, 255, 0)
)
final_line = create_line_mesh(
p1, p2, DB.ColorWithTransparency(0, 255, 0, 0)
)
dc3d_server.meshes = [start_cube, end_cube, final_line]
revit.uidoc.RefreshActiveView()
# Update UI state
if ui_instance:
distance = p1.DistanceTo(p2)
ui_instance.Dispatcher.Invoke(
framework.System.Action(
lambda: ui_instance.update_after_end_point(distance)
)
)
except Exception as ex:
print("Error picking end point: " + str(ex))
def GetName(self):
return "Pick End Point Handler"
class CreateLineHandler(UI.IExternalEventHandler):
def Execute(self, uiapp):
global p1, p2, dc3d_server, ui_instance
try:
if p1 and p2:
with revit.Transaction("Create Model Line"):
line = DB.Line.CreateBound(p1, p2)
sketch_plane = revit.doc.ActiveView.SketchPlane
if sketch_plane is None:
plane = DB.Plane.CreateByNormalAndOrigin(DB.XYZ.BasisZ, p1)
sketch_plane = DB.SketchPlane.Create(revit.doc, plane)
model_line = revit.doc.Create.NewModelCurve(line, sketch_plane)
print("Model line created successfully!")
# Clear preview meshes
dc3d_server.meshes = []
revit.uidoc.RefreshActiveView()
# Update UI state
if ui_instance:
ui_instance.Dispatcher.Invoke(
framework.System.Action(ui_instance.reset_ui)
)
except Exception as ex:
print("Error creating model line: " + str(ex))
def GetName(self):
return "Create Line Handler"
class PreviewLineUI(forms.WPFWindow):
def __init__(self):
global ui_instance, dc3d_server
# Create inline XAML
xaml_string = """
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Preview Line Tool"
Width="300" Height="340"
WindowStartupLocation="CenterScreen"
ShowInTaskbar="False"
Topmost="True">
<StackPanel Margin="20">
<TextBlock x:Name="txtStatus"
Text="Click 'Start' to begin"
FontSize="14"
Margin="0,0,0,20"
TextWrapping="Wrap"/>
<TextBlock x:Name="txtInfo"
Text=""
FontSize="11"
Foreground="Gray"
Margin="0,0,0,20"
TextWrapping="Wrap"
Height="50"/>
<Button x:Name="btnStart"
Content="Pick Start Point"
Height="35"
Margin="0,0,0,10"
FontSize="14"/>
<Button x:Name="btnEnd"
Content="Pick End Point"
Height="35"
Margin="0,0,0,10"
FontSize="14"
IsEnabled="False"/>
<Button x:Name="btnCreate"
Content="Create Model Line"
Height="35"
FontSize="14"
IsEnabled="False"/>
</StackPanel>
</Window>
"""
forms.WPFWindow.__init__(self, xaml_source=xaml_string, literal_string=True)
dc3d_server = revit.dc3dserver.Server(uidoc=revit.uidoc)
if not dc3d_server:
script.exit()
ui_instance = self
# Create external events
self.start_handler = PickStartPointHandler()
self.start_event = UI.ExternalEvent.Create(self.start_handler)
self.end_handler = PickEndPointHandler()
self.end_event = UI.ExternalEvent.Create(self.end_handler)
self.create_handler = CreateLineHandler()
self.create_event = UI.ExternalEvent.Create(self.create_handler)
# Wire up button events
self.btnStart.Click += self.on_start_click
self.btnEnd.Click += self.on_end_click
self.btnCreate.Click += self.on_create_click
self.Closed += self.form_closed
def on_start_click(self, sender, args):
self.txtStatus.Text = "Pick the start point in the view..."
self.start_event.Raise()
def on_end_click(self, sender, args):
self.txtStatus.Text = "Pick the end point in the view..."
self.end_event.Raise()
def on_create_click(self, sender, args):
self.txtStatus.Text = "Creating model line..."
self.create_event.Raise()
def update_after_start_point(self):
global p1
self.btnStart.IsEnabled = False
self.btnEnd.IsEnabled = True
self.btnCreate.IsEnabled = False
self.txtStatus.Text = "Start point selected. Move mouse to preview."
coord_text = "Start: ({0:.2f}, {1:.2f}, {2:.2f})".format(p1.X, p1.Y, p1.Z)
self.txtInfo.Text = coord_text
def update_after_end_point(self, distance):
global p1, p2
self.btnStart.IsEnabled = False
self.btnEnd.IsEnabled = False
self.btnCreate.IsEnabled = True
self.txtStatus.Text = "Both points selected. Ready to create line."
coord_text = "Start: ({0:.2f}, {1:.2f}, {2:.2f})\nEnd: ({3:.2f}, {4:.2f}, {5:.2f})\nLength: {6:.2f}".format(
p1.X, p1.Y, p1.Z, p2.X, p2.Y, p2.Z, distance
)
self.txtInfo.Text = coord_text
def reset_ui(self):
global p1, p2
p1 = None
p2 = None
self.btnStart.IsEnabled = True
self.btnEnd.IsEnabled = False
self.btnCreate.IsEnabled = False
self.txtStatus.Text = "Line created! Click 'Start' for another."
self.txtInfo.Text = ""
def form_closed(self, sender, args):
"""Clean up when form is closed"""
global tracker, idling_handler, dc3d_server, selection_handler
if tracker:
tracker.stop()
if idling_handler:
try:
HOST_APP.uiapp.Idling -= idling_handler
except:
pass
if selection_handler:
try:
HOST_APP.uiapp.SelectionChanged -= selection_handler
except:
pass
# Clear preview meshes
if dc3d_server:
dc3d_server.meshes = []
revit.uidoc.RefreshActiveView()
# Launch the modeless window
if __name__ == "__main__":
PreviewLineUI().Show()
Thanks pyrevit,
In effect, it looks very complicated. I have found more info on the Revit forum, and I understood that what I am looking for is called “rubber band” which is not available in Revit API.
I am now looking to create and visualise, at least, the first point, so the user can understand where it is. I will try to read your code and see how those circles appear in your case. I am not able to do the same with my code