First you must have a photo of a white object. So, if you want mock-up of a pants, you must have a photo of a white pants. This goes for all object you want mock-up off.
So, here I have a photo of a white pants.
Open this photo in Photoshop and with Quick selection tool select pants.
Now click on refine edge to smooth the selection.
Here you must play with your settings, sometimes you don’t have to do a thing. I just slightly changed some settings.
Then you click OK.
The best way is that you save this selection. Go to Select and click Save selection.
Window will appear.
You can name this selection and click OK.
Now you bring you design or pattern to Photoshop. You can copy it in AI and then paste it in Photoshop or you can bring a .jpg file to Photoshop. Here is my pattern.
When you bring your picture of pattern to Photoshop you lose a selection, that’s why we saved it before. Go to Channels and there you’ll find a mask of your selection. Now hold CTRL and click on that layer and now you have a selection of your object again.
Now go back to Layers, select layer of your pattern and click on a mask (if you look at the bottom where the layers are, you can see an icon for layer mask ).
Click on the mask and a mask will appear on that layer. Now you’ll have your pattern just on a pants.
If we look a bit closer, it doesn’t look good. Looks flat.
So that’s why we go to Blending options and select Multiply.
And now it looks great.
That’s how I do it, hope you liked it and learned something new.