Help with accurate perspective

Quite often I need to generate a rendered view of a model in order to
virtually place it into a background scene, usually a JPEG. I use Photoshop
to do the composite but I've had to take my models into Autocad in order to
create an accurate viewpoint / distance snapshot of the model so that it
appears to be in the proper place in the scene. I've been trying to get rid
of Autocad for years, is there a way to do an accurate camera position in
Solidworks? I've only been able to find the crude perspective setting (1,2,3
etc.) that doesn't seem to relate to anything in the real world. Help is
always appreciated, thanks in advance.

Gary Swink

 

Stefan Berlitz has a macro on his site that can do this.

Mike Wilson

 

The perspective numbers do relate to something in the real world - the model
size. Lets say you are rendering a breadbox thats maybe 2' across - the
perpective will be as if you were standing 2, 4, 6' away for a perpective of
1,2,3. Its kind of wierd, but I've gotten used to it. Makes some things
easy - I know that I would normally photograph a breadbox from about 5 feet
away, so I would use a perspective of 2.5. I've never bothered to see which
dimension is used on long thin things.

Lining up a model to a picture is quite easy. You will have to customize
your 'insert' and 'view-modify' menus in SolidWorks to even get the function
you need - its called insert.picture and modify picture, and allows you to
put an RGB TIFF image (sorry, no JPEG, and no CMYK art) into the background
of your SWx work space. You can then rotate the model and change the
perspective to match the virtual eactly to the real (ironically just did it
this afternoon, as a matter of fact).

The only catch when inserting pictures is that the picture proportions are
not constrained to the original proportions. It gets stretched to whatever
size your workspace area is.

I like to resize my workspace numerically so the picture is the right
proportion. I note the X and Y dimensions of my TIFF in my image software,
then create a sketch of a rectangle in SolidWorks that has that same X and Y
dim. Now I've got something dead on size that I can use as a local
reference for resizing my work window- I zoom in and out, and slide over the
bar that defines the feature manager area, until the sketch is exactly on
the edge of the work window. When I put my TIFF in, it will be the right
proportion.

Tip - 9 times out of ten, I get lazy and just make my tiff a square. Then I
draw a squre sketch in SWx that I will resize my workwindow to.

 

Ah, I found it...
http://swtools.cad.de/mm_20-readme.txt

Mike

 

I pretty much use the same method Ed uses with one difference. I use the
image (usually jpg format) as a background image in PhotoWorks. I then go
to photoWorks/ interactive rendering (check it to turn it on). My image
then shows in the background and I can adjust my model location and
perspective to match the picture. Once I save out the final rendering I
switch the background to a solid color for easy cropping. I then take the
rendered image and do the overlay on the background picture in Corel
PhotoPaint.

 

Thanks to everyone!
The macro is very nicely done and Rob's answer makes total sense. I'll
try them both. Maybe we can get Solidworks to add a camera position tool to
a future release.

Gary Swink