Rendering a Poser Figure against a Backdrop
This short tutorial will guide you through the steps needed to import a
Poser figure into Carrara using the Transposer and then to render them
against a backdrop, utilizing the power and reliability of Carrara's
rendering engine.
Clicking on some of the screen shots below will enlarge them to full
screen size.
Some of the instructions contain links which will bring up an
additional screen shots to clarify the process.
Remember that Carrara has multiple undos so if you move or change
something you didnt mean to it's easy to recover from the error.
1. Set the figure up in Poser
First run Poser and
add your figure with their costume and hair into the scene and put them
into the right pose. All of the correct materials should be
applied in Poser. Don't worry about setting up the lights in
Poser, although it is possible to import and convert the
lights using the Transposer. Carrara will pick up all of the
basic materials channels except for ray trace effects like reflection
and refraction.
Save the Poser scene in uncompressed or
compressed format.
This tutorial uses the Aiko 3.0 figure with the Maps and Morphs package
and clothing items from the Lotus for Aiko 3.0 set. The hat is
from the Poser 5 props library.
2. Import the figure into Carrara
Run Carrara and
start with a new empty scene.
Choose File | Import then use the browser to locate the Poser scene you
just saved.
Use all of the default import options except to change it not to bring
in the Poser lighting because we want to use Carrara lights.
Leave the scale as the default. After you hit the Ok button to
load it may take a moment for the progress indication bar to come up,
even on a fast computer.
It is important to leave the option to Keep link to Poser file
checked. If the Poser scene changes then you will be able to
update the figure imported into the Carrara scene. If this option
is unchecked then the materials will all come in correctly but they
will not be named and so are difficult to edit.
3. Load up the Backdrop
In Poser you normally import a background picture and this appears
behind the figure. This feature is available in Carrara but its
called
a 'backdrop' instead. A backdrop could be a 2D drawing,
photograph or
a render from Carrara or another application. Note that in
Carrara there is a
difference between a background and a backdrop in that a backdrop
is a fixed image that follows the camera but a background is intended
for 360º panoramic images and is consistenly projected around the
whole
scene.
Make
sure that the Properties tray is rolled out. Click on the handle on the
right side of the 3D view if it's not. You can click on the
handle of the Sequencer tray, which is at the bottom of the screen, to
close it and gain more space.
The bottom panel should be showing the <Instances> card and a
lists of all the things that are in the scene. Click where it
says Scene at the top of the list to select it. An alternative
method is to use the application menu and choose Edit | Edit Scene
Effects. Now look up higher at
the list of roll-outs in the Properties tray and click on the little
arrows or where it says 'None' to add a Backdrop to the scene.
The backdrop is going to
be an image map, so select Map from the popup list.
Load
the image by clicking on the higher icon of a folder.
After locating the image file on your disc a dialog will come up
prompting you to choose the file format. This is to allow the
user to have the option of loading up a sequence of background images
for an animation, simply stick with the default choice of a single
image and hit ok.
You'll need to see the backdrop in the 3D view and so you must change
the view options to do this. Click on the icon of a circle with
an arrow pointing up that is just above the 3D view and to the left of
the preview display shading icons. This brings up the Interactive
Render Settings dialog. In the display options section put a tick
in the box to show backdrop.
It will help to hide the sides of the working box grid Click once
on the icons just above the 3D view till they are dimmed out and that
grid goes away.
4. Adjust the Render Resolution
The
rendered image size should match the picture or it will be
distorted. Take note of the image resolution of the backdrop.
Move to the Render room where the contents of the properties tray now
changes. Switch to the <Output> card.
Set the image dimensions, most importantly the same aspect ratio, to
match the image. Unchecking the Keep Proportions setting will
allow you to change either dimension freely without Carrara adjusting
the other. This is like the Constrain
aspect ratio setting in Poser when you set the document window
size or the render output size.
Return to the assembly room and the 3D scene view by clicking on the
icon of a hand at the top of the application window.
5. Position the Camera
In Poser
normally when you start up a render the current view that you see in
the preview window is filled - that is unless the render is done in a
new window with different
proportions.
Carrara doesn't give the same kind of simple exactly 'what you see is
what you get' render. In Carrara you must use the production
frame. To show the production frame use the top application menu
and select View | Show Production Frame. The production frame
appears as a white box with a cross hair in the middle. It's sort
of like looking at the LCD screen on a digital camera as compared to
looking through the view finder.
It's
important to note that the 3D view of your scene
doesn't have a fixed size.
You can float the window by double clicking on the scene title or by
changing the Windows | Maximized Window Mode option. When its
floated you can freely resize the window and in maximized mode its'
size can also change when you roll out the properties tray or the
sequencer tray. The 3D view size will also depend on your desktop
resolution.
However the final render size and its proportions do not change and
what you see inside the production frame is what you get when you
render. You can change views, do test renders in a smaller area,
switch to and use other cameras freely but the final render will show
what's in the production frame for Camera 1.
You can position the camera using the track and
dolly controls much the same was as you do in Poser except that in
Dolly mode the camera will orbit around the current selection. If
there is no selection or the scene is selected the camera will orbit
around the origin.
Camera 1 should be selected as the current
camera. Click on the camera name if
its
not then select Camera 1 from the popup list. Select the
figure in the scene
list and then swing the camera around till it faces them from the
correct angle.
Notice that
the backdrop image is always projected the same way and always behind
the objects
in the scene - no matter where the camera moves. Use the track
controls to line the
figure up in the production frame so that it's all to your liking and
consistent with the backdrop.
For an extra tip, the horizon line of the Carrara
scene
should exactly match with the one clearly visible in the
photograph. You'll need to somehow see the horizon line to be
able to do this though and Carrara doesn't have a feature exactly like
that. The working box grid normally only covers a short distance
so what you need to do is make the XY ground plane grid so massive
that it dissappears to the horizon.
Use
the top application menu and choose View | Grid to bring up the Grid
dialog.
Change the size parameters of the grid so it's 100,000 units large
! You will also need to set the spacing size to be 100 units and
draw a line every 1 or the grid will have too many lines. You
also need to set the centre of the working box so that the bottom of
the grid is at zero or ground level. This is done by changing the
Center Z value so that the middle of the working box is positioned to
be at half the height of the working box - that is 50,000 units.
If the grid isnt visible use the little icons above the 3D view to show
the bottom XY plane. It may help to change the colour of the grid
using File | Preferences and the 3D View Colors options to make it
easier to see.
Then,
finely adjust the camera, the subject,
background
and the vanishing grid showing an effective the horizon line till they
are all positioned properly and look consistent.
By clicking on the little triangle next to the camera trackball you can
select from one of three modes. Use the Bank mode for the camera
to roll the horizon if the original photograph isnt quite level.
Click on that icon again to change back to Dolly mode. In Poser
the Roll controls is the equivalent of bank and its a small dot next to
the main trackball.
Set the working box and grid back to the previous size manually by
using the grid
dialog when the camera is set. An alternative way is to choose
View | Send Working Box to Origin then only the spacing needs to be
changed back to 1 in the Grid dialog.
You can lock the camera into position to
prevent accidental changes by selecting it from the scene list then
switching the properties card above to <Motion>. Click
where it says Constraint: 'None' and choose Lock from the popup
list. If you need to move the camera again later change the
constraint back from Lock to None.
6. Adjust the Lighting
Some scenes will demand much more complex lighting than this example
but the default
distant light is fine to generate basic sunlight. To get the
lighting to work for the scene we must adjust the direction and
strength of the distant light so that it
matches conditions of the backdrop. A distant light in Carrara
behaves
just
like one in Poser in that it doesn't matter where the light is located
but in which direction it's pointing. We want to be able to
adjust the light in real time and see the results on the figure as
easily as you can in Poser. By moving the distant
light
object in the scene so that is up close to the figure's head then we
will be able
to look through the camera, adjust the light and see the figure and
backdrop all at the same
time.
Use
the Director's Camera with all sides of the working box visible or the
Top and Left views to move the light very close to the
figure's head. If the Grid has not been reset to a smaller size,
like 30 units, following the previous step then the scene will be a
tiny dot somewhere if you try to switch the camera to the Top of Left
view.
Click on the Camera name in the top right corner of the 3D view or hit
the icons above the middle of the 3D view to choose from one of the
alternate split screen viewing modes.
Select the Light 1 in the Scene list on the properties tray then drag
and drop it into the right position or use the manipulator tool by
clicking and dragging on one of the coloured arrow heads over the light.
Click on the One View icon and then select Camera 1 as the current
viewing camera to return to the previous 3D view arrangement.
To
be able to see the preview properly you will need to change the
Interative Render Settings again. Click on the circled arrow just
above the 3D view to bring up the dialog. This time change the
Lighting Mode options
to use the 'Scene lights' and hit Ok.
Now you will be able to adjust the light and see the changes
interactively.
Make
sure that you are viewing the scene through Camera 1. Select
Light 1 from its arrow like object in
the 3D view window or by name from the scene list in the Properties
tray. Use the
Rotate tool and then the manipulation curves or click on the light and
use
small movements to adjust it.
You want the light cast on the
figure to match the scene lighting in the backdrop. Look for
clues in the scene on rounded
objects. This example has rocks which makes it easy to see that
the
light is coming down into the scene from the right. Shadows cast
by sharp
edges or the darker tones on rounded surfaces will tell you how steep
the angle of the light is. Note where the highlights are hitting
the surface and rotate the light so that the highlights on the figure's
face are
consistent with the background.
This is where the lit ball in Poser would have helped. Sometimes
it's worth inserting a sphere primitive and a box into the Carrara
scene, temporarily, to help get the lighting right.
Now
you need to adjust the ambient light to match the backdrop. Poser
doesn't have a global ambient light control. Ambient light is
uniformly added to every texture in the scene when rendered and sets
how dark surfaces in full shade will be. If the shadows are
totally black,
and this is never the case in real daylight, then the ambient light
will be
0%.
The ambient light value can be adjusted by first selecting the Scene
from the list on the properties tray and then by looking up and
expanding the Ambient roll out. Double click on where it says
Ambient or on the triangle to the left of it. Use the slider, the
colour chip or click on the number and type in a value to set the
ambient light level.
Unfortunately there is a bug in the
current version of Carrara (5.1) and you must switch rooms for
it to catch up with any
adjustments made to ambient light !
It is better to use clues from the picture itself as to how dark
the shadows are. Observe how dark a rounded surface is shaded on
the side away from direct light or how dark shadows are out in the
open. It can help to open up the same backdrop image in a 2D
paint application and use a colour tester tool
(the usual icon is a pipette) then look at the HSL value and copy the
Lightness. Set the
ambient brightness in Carrara to match that value, in this example the
lightness value of the pixels on the under-surface of a rock is about
15%.
7. Render the Figure
First keep the default render settings as they are and use the Test
Render tool on part of the figure. Select the camera icon at the far lower left then
click and drag a box over the figure and wait. Press the Escape
button to abort a test render if its taking too long.
Check the result, but dont touch any of the tools or click anyware
until you have or it will vanish, and then make any
further adjustments to the strength of the main light and the ambient
light if they don't quite seem right yet. If the shadows and
darks are too bright
compared to those in the backdrop then reduce the ambient light
brightness and try again. If the highlights are too soft then
increase the Brightness value
of the main distant light. Do this by selecting it from the scene
list in the Properties tray and make sure you have selected the
<General> card to type a value, change the colour or move the
slider.
When
you are ready for a proper render move to the Render Room or choose
Windows | Render Scene from the application menu.
To start a render in the Render room roll out the bottom tray if its
closed then hit the Render or Render in New Window button. A bar
will show your progress at the bottom of the screen.
It is best not to leave the render room while waiting for it to finish
but it's ok to switch to another application.
For
the highest render quality check the Full Raytracing option. Also
change the Anti-Aliasing quality to Best so that Carrara takes more
samples and blends the resulting values together. Change the
Object and Shadow accuracy values to 0.5 pixel for higher
accuracy. Also turn up the Maximum Ray Depth to the highest
value, the default of 8 is ok for characters with hair though but when
using trees with transparent leaf textures and figures together you
must go higher. Another good way to get higher accuracy and more
detail for a still image is to render at double or 4 times the required
size then to save and shrink the image down in a 2D paint or photo
application.
To save the render choose File | Save As or do so when prompted after
closing the window.
8. Adding More Realism
Using the Sky Light rendering feature will give a noticeably more
realistic result. This doesn't need a Carrara sky or a scene full
of props
to work.
To replace the flat ambient lighting in this scene,
and to match closer
to the
colours from the photograph, load the same image in as a background
! The backdrop will still be rendered first,
that is infront of the background, but the colours from the background
will be cast back into the scene. The figure will pick up subtle
changes in colour to match with the colours from the photograph.
HDRI background images are generally favoured to get the best results
but with a directional
light and the
same photograph you can still get great results.
Return to the
Assemble room and turn the ambient light brightness down to 0% - but
leave the
distant light as it is.
Load the background the same way as the backdrop. You will find
it higher up in the Scene effects in the properties tray.
Move back to the render room again and change the
setting in the Global Illumination to enable Sky Light. Leave the
other GI settings as the defaults then run another test render.
Now the shadows have come to life.
At the default quality the sky light will create a slightly dirty
looking, patchy result so we need to change the settings to improve
it. Increasing both the Interpolation precision value to 100% and
the Photon Map accuracy to 100% will improve the render without slowing
it down too much. Changing the Lighting Quality to 'Good' and the
Accuracy to 4 pixels will gain smoother results. The rendering
time will now be slower, but if the photon count is kept low it should
take less than 15 minutes on a 3Ghz dual processor.
Using very high quality settings for GI will cause very slow renders
which are best left to run overnight. In this example most of the
render shows the backdrop image and these parts render instantly, where
the figure and other scene objects appear it will slow down. If
the figure dominates the scene the render will be much slower.
For the final render you should check the option to render Light Through transparency as
this will be needed for the GI to work through hair, eye lashes and
eyebrows. This is especially important when the figure is
rendered up close and the lighting quality and accuracy may need to be
set to the best quality to avoid artefacts caused by eyebrows and
eyelashes with transparency maps. Using light through
transparency will approximately triple the rendering time.
As a test try turning all the lights off in the scene
and use only the
Sky
Light from the photograph to see its contribution to the realism.
Try increasing the sky light intensity to 200% so that the result is
brighter. The figure looks like they are standing in the
photograph but in shadow. Note how tangible, soft and 3
dimensional the surfaces look now.
That ends the tutorial...
For any feedback, comments or questions email me,
Jeremy@Sparrowhawke3D.com
www.Sparrowhawke3D.com
Make
sure that the Properties tray is rolled out. Click on the handle on the
right side of the 3D view if it's not. You can click on the
handle of the Sequencer tray, which is at the bottom of the screen, to
close it and gain more space.
Load
the image by clicking on the higher icon of a folder.
The
rendered image size should match the picture or it will be
distorted. Take note of the image resolution of the backdrop.
It's
important to note that the 3D view of your scene
doesn't have a fixed size.
Camera 1 should be selected as the current
camera. Click on the camera name if
its
not then select Camera 1 from the popup list. Select the
figure in the scene
list and then swing the camera around till it faces them from the
correct angle.
Use
the top application menu and choose View | Grid to bring up the Grid
dialog.
Then,
finely adjust the camera, the subject,
background
and the vanishing grid showing an effective the horizon line till they
are all positioned properly and look consistent.
Use
the Director's Camera with all sides of the working box visible or the
Top and Left views to move the light very close to the
figure's head. If the Grid has not been reset to a smaller size,
like 30 units, following the previous step then the scene will be a
tiny dot somewhere if you try to switch the camera to the Top of Left
view.
To
be able to see the preview properly you will need to change the
Interative Render Settings again. Click on the circled arrow just
above the 3D view to bring up the dialog. This time change the
Lighting Mode options
to use the 'Scene lights' and hit Ok.
Make
sure that you are viewing the scene through Camera 1. Select
Light 1 from its arrow like object in
the 3D view window or by name from the scene list in the Properties
tray. Use the
Rotate tool and then the manipulation curves or click on the light and
use
small movements to adjust it.
Now
you need to adjust the ambient light to match the backdrop. Poser
doesn't have a global ambient light control. Ambient light is
uniformly added to every texture in the scene when rendered and sets
how dark surfaces in full shade will be. If the shadows are
totally black,
and this is never the case in real daylight, then the ambient light
will be
0%.
When
you are ready for a proper render move to the Render Room or choose
Windows | Render Scene from the application menu.
For
the highest render quality check the Full Raytracing option. Also
change the Anti-Aliasing quality to Best so that Carrara takes more
samples and blends the resulting values together. Change the
Object and Shadow accuracy values to 0.5 pixel for higher
accuracy. Also turn up the Maximum Ray Depth to the highest
value, the default of 8 is ok for characters with hair though but when
using trees with transparent leaf textures and figures together you
must go higher. Another good way to get higher accuracy and more
detail for a still image is to render at double or 4 times the required
size then to save and shrink the image down in a 2D paint or photo
application.
To replace the flat ambient lighting in this scene,
and to match closer
to the
colours from the photograph, load the same image in as a background
! The backdrop will still be rendered first,
that is infront of the background, but the colours from the background
will be cast back into the scene. The figure will pick up subtle
changes in colour to match with the colours from the photograph.
HDRI background images are generally favoured to get the best results
but with a directional
light and the
same photograph you can still get great results.
Move back to the render room again and change the
setting in the Global Illumination to enable Sky Light. Leave the
other GI settings as the defaults then run another test render.
Now the shadows have come to life.
As a test try turning all the lights off in the scene
and use only the
Sky
Light from the photograph to see its contribution to the realism.
Try increasing the sky light intensity to 200% so that the result is
brighter. The figure looks like they are standing in the
photograph but in shadow. Note how tangible, soft and 3
dimensional the surfaces look now.