= How to |> render wireframes =

This method works with polygons, primitives, nurbs, and metaballs.

== Create a scene ==

# Create a grid by clicking the [Icon:SOP/grid][Grid|Node:sop/grid] tool on the __Create__ shelf tab.

# Create a teapot by clicking the [Icon:SOP/platonic][Platonic Solids|/shelf/platonic] tool on the shelf and changing the __Solid Type__ to `Utah Teapot`.

# Click the [Environment Light|/shelf/lightsandcameras] on the __Lights and Cameras__ shelf tab to create some [ambient occlusion|/light/ambientocclusion].

    [Image:/images/howto/wireframe_teapot.png]

# On the [Material Pallette|/ref/panes/materialpalette] select a shader and drag it onto the grid and teapot. 
    For this example we will use the [Clay material|/gallery/shop/material/clay].
    
== Render the scene ==

# Create a [camera|/shelf/lightsandcameras] by ((Ctrl + LMB)) the camera on the __Lights and Cameras__ shelf tab. 

# Create a [mantra render node|Node:out/ifd] by clicking __Render > Create Render Node > Mantra__ in the Houdini menu.

# Render your image.
    The following is what your default rendered image will look like.
        [Image:/images/howto/wireframe_defaultrender.png]
    
# Improve the quality of your render by navigating to the __Light__ tab on the environment light, by clicking the __Area Light Options__ subtab and increasing the __Area Samples__ parameter to `256`.

# Render the image again.
    The following is what your new rendered image will look like.
        [Image:/images/howto/wireframe_newrender.png]
        
# Save the image and close [MPlay|/mplay].

== Render the scene with wireframes ==

# Turn off the display of any objects you don't want visible, such as the environment light. 

    NOTE:
        To turn off the display of the light handles, press ((Esc)).
        
# Click the __Shading mode__ button at the right side of the viewer toolbar and choose [Icon:VIEW/hiddenline] __Hidden Line Invisible__.

    [Image:/images/ui/viewer_toolbar1_anno.png]
    
    [Image:/images/howto/wireframe_invisible.png]

# ((RMB)) the [Icon:TOOLS/flipbook] [Flipbook|/ref/windows/flipbook] icon and choose __Flipbook with New Settings__.

# On the __Output__ tab, change the __Frame Range/Inc__ to: `1, 1, 1` since it is a still image.

# On the __Effects__ tab, enable the __Depth of Field__ and increase the __Quality__ to something much higher, such as `16`.

# On the __Size__ tab, set the __Resolution__ to the same as the __Resolution__ on the __View__ tab of your camera. In this example it is `640x480`.

    You can also turn on __Crop Out View Mask Overlay__.
    
# Press __Accept__ and render your image.

    [Image:/images/howto/wireframe_render1.png]
    
    This render will also produce a nice looking alpha channel.
    
    [Image:/images/howto/wireframe_alpha.png]
    
# Save the image again and close [MPlay|/mplay].

== Composite the two renders ==

# Switch the view to __Composite View__ and switch to the [Icon:NETWORKS/cop2] img network.

# Dive into the [Icon:NETWORKS/cop2] Compositing network and create a [Icon:COMMON/file] [File|Node:cop2/file] node using the [Tab menu|/basics/tabmenu].

# Change the __File__ from `default.pic` to your wire render.

# Create another [Icon:COMMON/file] [File|Node:cop2/file] node using the [Tab menu|/basics/tabmenu] and change the __File__ from `default.pic` to your original render.

# Insert a [Multiply|Node:cop2/multiply] node and connect the two file nodes to the inputs. 

    [Image:/images/howto/wireframe_nodes.png]
    
    This will make the entire image darker because you are multiplying the entire color channel.

    [Image:/images/howto/wireframe_multiply.png]

# Connect the wire file to the mask input, which will use the alpha channel from the wire file.
    
    [Image:/images/howto/wireframe_nodes2.png]

    [Image:/images/howto/wireframe_mask.png]