If I understand your question correctly you're interested in investigating the energy effects of different structural components of a building's construction. With that in mind here's some information that might be helpful:
As you may know the OpenStudio SketchUp Plugin is primarily used to create geometry for a building energy model. EnergyPlus, the simulation engine that OpenStudio uses, doesn't require the user to explicitly define 3D surfaces. Instead, 2D surfaces are assigned constructions which are made up of layers of materials. The properties of these individual materials, including thickness, are what determines the the energy performance of the building envelope.
In other words, it's not necessary to create beams and columns in the OpenStudio SketchUp Plugin to simulate the energy performance - all that's required is a 2D OpenStudio surface created in SketchUp. Once you migrate to the OpenStudio Application to finish the model you can define the properties of your beam and column construction(s).
Note that this will require an understanding of conduction heat transfer in order to properly define the overall thermal properties of the beam and column ceiling, floor, and/or wall construction (including air gaps, insulation, etc.). Here are some previous questions that might help:
https://unmethours.com/question/747/h...
https://unmethours.com/question/1065/...
From an energy modeling standpoint the structural members of the building (beams and columns) matter if they create thermal bridges through the building envelope. Search for "thermal bridges" in the context of energy modeling.
Also, please move the question about constructions in OpenStudio into a separate question (this site does 1 question per...question).
@Stephanie12 if you move the construction portion to a new question, I'll move the answer there as well.
I just want to know if the different in the results, it will be huge without columns and beams?
@Stephanie12, the answer, as ever, is "it depends".
I am not an architect and Ι trying to learn the google sketchup on my own. If I want to design the columns and beams, how can this be done? And if this will be, how I will design the walls with the correct thickness;