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How to Draw a Proper Round Diamond in SolidWorks (Using Adanced Design)

Tutorial by George Haddad Sabounjian
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I've been always interested in modeling a Proper Round Diamond. after doing some research i came across bunch of models. But unfortunately almost all of them were modeled wrong. after digging deeper into how they are cut I started modeling my own Round Brilliant Diamond using only equations and relations.

I felt like sharing this experience with amazing GrabCAD community.

Hope you Enjoy it!
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Before starting I would highly suggest you to spend some time reading about Round Brilliant Diamond cut and get familiar with it's facet names, and know how Diamond proportions work.
Useful links:
https://en.wikipedia.org/wiki/Brilliant_(diamond_cut)
http://www.jewellerycatalogue.co.uk/diamonds/round-brilliant.htm
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I also made a video tutorial of the model
(insert Youtube link)

you can download the SolidWorks model here
(insert GrabCAD link)

  1. Step 1: Global Variables

    In this step we first set up our Global Variables.

    go to Tool > Equations then set the following values under Global Variables.

    •Diameter = 16mm

    •Crown Angle = 33.36deg

    •Pavilion Angle = 40.48deg

    •Girdle Thickness = 1.5%

    •Crown Height = 14.45%

    •Pavilion Height = 43.15%

    •Lower Girdle Facet Length = 40%

    •Total Depth = 59%

    Click OK.


  2. Step 2: Section Sketch

    Open a new sketch on Front Plane and draw a section of the diamond.

    Then use the Global Variables we set in Step 1 to fully define your sketch.

    Use the following variables only (Crown Angle, Pavilion Angle, Crown Height, Pavilion Height and Girdle Thickness)

    *Make sure to use Equal sign before Global Variables. Otherwise your dimensions won't be linked to your equations.

    Rename the sketch as Section Sketch.

    This sketch will be used mostly as a reference.

  3. Step 3: Diameter Cylinder

    Open a new sketch on Top Plane.

    Draw a circle from origin and link the diameter to Global Variable "Diameter"

    Use extrude surface on the circle.

    •For direction 1 end condition select [up to vertex] then select one of table vertices (Pink) as shown in the picture.

    •For direction 2 end condition select [up to vertex] then select the culet point (Purple) as shown in the picture.

    This surface will be used mostly as a reference.

    Hide the surface.

  4. Step 4: Creating Table Facet

    First create a plane using parallel to top plane and coincident to one of table vertices from Section Sketch as reference.

    Rename the plane as Table Plane.


    Start a sketch on Table Plane and draw an octagon starting from the Origin and fully define it by adding coincident relation between one of octagon's vertices and table vertex from Section Sketch.


    Use planer surface to create Table Facet.


  5. Step 5: Creating Kite Facets

    -Open a new sketch on Front Plane and convert crown line from Section Sketch.

    -Use extrude surface to create the Kite Facet.

    •For direction 1 end condition select [up to vertex] then select a vertex from Table Facet (Pink) as shown in the image below.

    •For direction 2 end condition select [up to vertex] then select the opposite vertex from Table Facet (Purple) as shown in the image below.


    Next we will create the trim tool for Kite Facet.


    -First unhide the Diameter Cylinder Surface we hid on Step 3.

    Open a new sketch on Table Plane and sketch a kite shape with the following relations.

    (note that the kite shape ends on Diameter Cylinder surface)

    Exit the sketch.


    -Select Trim Surface command and trim the outer parts of the surface (blue area).



    -Now using Circular Pattern create the rest of the Kite Facets.

    (Make sure the equal spacing is ticked while applying Circular Pattern.)

  6. Step 6: Creating Star and Upper Girdle Facets

    -Use Planer Surface to create a Star Facet between two Kite Facets and Table Facet.

    Next we will create an Upper Girdle Facet.

    Hide Diameter Cylinder Surface.


    -First create a plane using the following references.

    •Reference 1: Culet point @ Section Sketch (Pink)

    •Reference 2: Star Facet we just created (Purple)

    •Reference 3: Outter Star Facet vertex (Green)

    Rename the plane to Girdle Plane.


    Unhide the Diameter Cylinder Surface. and hide Section Sketch.


    -Open a new Sketch on Girdle Plane and draw a line starting from outer vertex of Star Facet and add the following relation to it's end point.

    (make sure u have normal to plane view while doing this)

    Horizontal with Kite Facet outer vertex.Vertical with Edge of the Diameter Cylinder.

    The line should be fully defined.

    -Use Boundary Surface to create an Upper Girdle Facet by selecting the line we just sketched and outer edge of Kite Facet for direction 1 as shown in the image below.

    Hide Girdle Plane and Diameter Cylinder.

    -Unhide Section Sketch, and extend the Upper Girdle Facet that we just created using Extend Surface command. for end condition select [up to point] then select Culet point from Section Sketch.


    Unhide Diameter Cylinder.


    -Select Surface Trim command and trim the Upper Girdle Facet using Diameter Cylinder as a trim tool.




    Hide Diameter Cylinder. and unhide Girdle Plane.


    -Select Mirror command and mirror Upper Girdle Facet using Girdle Plane as [Mirror Face/Plane].


    Unhide Diameter Cylinder.


    -Now using Circular Pattern complete the crown.

    For parameters:

    •Pattern Axis use Diameter Cylinder.

    •Pattern Angle = 360deg

    •Number of instances = 8

    for Bodies to Pattern select all three Facets that we created in this Step.

    (Make sure the equal spacing is ticked while applying Circular Pattern.)



    Hide Diameter Cylinder.










  7. Step 7: Creating Pavilion Main Facet

    -Open a new sketch on Front Plane and convert Pavilion line from Section Sketch.

    -Use extrude surface to create the Main Pavilion Facet.

    •For direction 1 end condition select [up to vertex] then select a vertex from Table Facet (Pink) as shown in the image below.

    •For direction 2 end condition select [up to vertex] then select the opposite vertex from Table Facet (Purple) as shown in the image below.

    Next we will create the trim tool for Pavilion Main Facet.


    Hide the Girdle Plane. And unhide the Diameter Cylinder.


    -Open a new sketch on Front Plane and sketch a kite shape with the following relations. Also add Linked Dimension for Lower Girdle Facet Length.

    (note that the kite shape ends on Diameter Cylinder surface)


    -Select Trim Surface command and trim the outer parts of Pavilion Main Facet (blue area) using the sketch we just creating as trim tool.


  8. Step 8: Creating Lower Girdle Facet

    Hide Section Sketch and unhide both Diameter Cylinder & Girdle Plane.


    -Open a new sketch on Girdle Plane and set the view "Normal to" and display style to "Hidden Lines Visible" then draw a line with the following relations.

    •Start point of the line is coincident with Pavilion Main Facet's mid vertex.

    •End point of the line is coincident with edge of the Diameter Cylinder and Horizontal with Pavilion Main Facet's outer vertex.

    The line should be fully defined at this point.


    -Use Boundary Surface to create a Lower Girdle Facet by selecting the line we just sketched and outer edge of Pavilion Main Facet for direction 1 as shown in the image below.

    -Extend the Lower Girdle Facet that we just created using Extend Surface command. for end condition select [up to surface] then select Table Facet.


    Unhide Diameter Cylinder.


    -Select Surface Trim command and trim the Lower Girdle Facet using Diameter Cylinder as a trim tool.


    Hide Diameter Cylinder.


    -Select Mirror command and mirror Lower Girdle Facet using Girdle Plane as [Mirror Face/Plane].


    Hide Girdle Plane and Unhide Diameter Cylinder.


    -Now using Circular Pattern complete the Pavilion.

    For parameters:

    •Pattern Axis use Diameter Cylinder.

    •Pattern Angle = 360deg

    •Number of instances = 8

    for Bodies to Pattern select all three Facets that we created in Step7 & Step 8.

    (Make sure the equal spacing is ticked while applying Circular Pattern.)



    Hide Diameter Cylinder.

  9. Step 9: Creating Girdle

    -Select Boundary Surface command and create a surface between Upper and Lower Girdle Facets.


    -Select Boundary Surface command again and create another Girdle Surface next to the one we just created.

    (it really doesn't matter on which side you make the surfaces as long as they are next to each other)


    Unhide Diameter Cylinder.


    -Use Circular Pattern command to finish the rest of the Girdle.

    For parameters:

    •Pattern Axis use Diameter Cylinder.

    •Pattern Angle = 360deg

    •Number of instances = 8

    •Bodies to Pattern select all both Girdle Facets that we created in this Step.

    (Make sure the equal spacing is ticked while applying Circular Pattern.)


    -Using Delete/Keep Body feature command delete Diameter Cylinder.

  10. Step 10: Adding the Culet

    -Using Knit Surface command Knit all surfaces we created so far. and Make sure to tick "Create solid" option.


    -Open a new sketch on Front Plane and draw a horizontal line on Pavilion. add coincident relation between Girdle Facets and it's end points.

    Add Dimension between the line and the Table Facet and link it to Global Variable "Total Depth".




    -Using Extrude Surface command a surface with "Through All" end condition for both directions.


    -Using Cut With Surface feature command remove the pointy end of the Pavilion to form the Culet.


    -Using Delete/Keep Body feature command delete the surface we created in this Step.


    Summary:

    Modeling the Diamond in this way will let us change the Diameter value in Global Variables anytime without having to model the diamond from Scratch or reapply any command.


    The End.

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