We have a requirement, wherein a customer will be allowed to add only one product to the cart at a time. However he/she can add any quantity of that product.

How can I prevent a product from adding to cart if there is already a product present in the cart?

Can some one help on this?


Question: Is netrender only useful for multiple frames?
Answer: You cannot use Network Render to render a single frame out-of-the-box. However, it is possible with some tweaking and post-processing.

First, extend your timeline to however many slaves you are going to use. If different slaves have different hardware configurations, you may want to multiply this by two to render slightly faster.

Then, in the Properties &rarr; Render Settings &rarr; Sampling, select the Seed field and enter the text #frame. Press Enter. (If you see a message indicating that the driver will not be automatically run, either enable autorun for drivers or reload the file as trusted; don't forget to save.) This will tie the interpolator seed to the current frame.

Then, take the Render Samples value and divide it by the number of frames in your timeline.

You can now perform a network render of your file. When your "video" is finished, you can blend the files together to obtain the final image.